diff --git a/bamboo-specs/release.yaml b/bamboo-specs/release.yaml
index dc9acae9..bfdfff3b 100644
--- a/bamboo-specs/release.yaml
+++ b/bamboo-specs/release.yaml
@@ -109,7 +109,8 @@
                 CHANNEL=${bamboo.channel}\
                 GPG_KEY_PASSPHRASE=${bamboo.gpgPassword}\
                 FRONTEND_PREBUILT=1\
-                VERBOSE=1\
+                PARALLELISM=1\
+                VERBOSE=2\
                 build-release
   # TODO(a.garipov): Use more fine-grained artifact rules.
   'artifacts':
@@ -239,18 +240,12 @@
               ;;
         esac
 
-        # Ignore errors from the Snapstore upload script, because it seems to
-        # have a lot of issues recently.
-        #
-        # TODO(a.garipov): Stop ignoring those errors once they fix the issues.
-        #
-        # See https://forum.snapcraft.io/t/unable-to-upload-promote-snaps-to-edge/33120.
         env\
                 SNAPCRAFT_CHANNEL="$snapchannel"\
                 SNAPCRAFT_EMAIL="${bamboo.snapcraftEmail}"\
                 SNAPCRAFT_MACAROON="${bamboo.snapcraftMacaroonPassword}"\
                 SNAPCRAFT_UBUNTU_DISCHARGE="${bamboo.snapcraftUbuntuDischargePassword}"\
-                ../bamboo-deploy-publisher/deploy.sh adguard-home-snap || :
+                ../bamboo-deploy-publisher/deploy.sh adguard-home-snap
   'final-tasks':
   - 'clean'
   'requirements':
diff --git a/client/src/__locales/en.json b/client/src/__locales/en.json
index 1771afbd..f653bc37 100644
--- a/client/src/__locales/en.json
+++ b/client/src/__locales/en.json
@@ -298,6 +298,9 @@
     "blocking_mode_nxdomain": "NXDOMAIN: Respond with NXDOMAIN code",
     "blocking_mode_null_ip": "Null IP: Respond with zero IP address (0.0.0.0 for A; :: for AAAA)",
     "blocking_mode_custom_ip": "Custom IP: Respond with a manually set IP address",
+    "theme_auto": "Auto",
+    "theme_light": "Light",
+    "theme_dark": "Dark",
     "upstream_dns_client_desc": "If you keep this field empty, AdGuard Home will use the servers configured in the <0>DNS settings</0>.",
     "tracker_source": "Tracker source",
     "source_label": "Source",
diff --git a/client/src/actions/encryption.js b/client/src/actions/encryption.js
index 2f58abd3..5db97607 100644
--- a/client/src/actions/encryption.js
+++ b/client/src/actions/encryption.js
@@ -41,6 +41,12 @@ export const setTlsConfig = (config) => async (dispatch, getState) => {
         response.certificate_chain = atob(response.certificate_chain);
         response.private_key = atob(response.private_key);
 
+        if (values.enabled && values.force_https && window.location.protocol === 'http:') {
+            window.location.reload();
+            return;
+        }
+        redirectToCurrentProtocol(response, httpPort);
+
         const dnsStatus = await apiClient.getGlobalStatus();
         if (dnsStatus) {
             dispatch(dnsStatusSuccess(dnsStatus));
@@ -48,7 +54,6 @@ export const setTlsConfig = (config) => async (dispatch, getState) => {
 
         dispatch(setTlsConfigSuccess(response));
         dispatch(addSuccessToast('encryption_config_saved'));
-        redirectToCurrentProtocol(response, httpPort);
     } catch (error) {
         dispatch(addErrorToast({ error }));
         dispatch(setTlsConfigFailure());
diff --git a/client/src/actions/index.js b/client/src/actions/index.js
index 2242490b..d86ea43e 100644
--- a/client/src/actions/index.js
+++ b/client/src/actions/index.js
@@ -363,18 +363,18 @@ export const changeLanguage = (lang) => async (dispatch) => {
     }
 };
 
-export const getLanguageRequest = createAction('GET_LANGUAGE_REQUEST');
-export const getLanguageFailure = createAction('GET_LANGUAGE_FAILURE');
-export const getLanguageSuccess = createAction('GET_LANGUAGE_SUCCESS');
+export const changeThemeRequest = createAction('CHANGE_THEME_REQUEST');
+export const changeThemeFailure = createAction('CHANGE_THEME_FAILURE');
+export const changeThemeSuccess = createAction('CHANGE_THEME_SUCCESS');
 
-export const getLanguage = () => async (dispatch) => {
-    dispatch(getLanguageRequest());
+export const changeTheme = (theme) => async (dispatch) => {
+    dispatch(changeThemeRequest());
     try {
-        const langSettings = await apiClient.getCurrentLanguage();
-        dispatch(getLanguageSuccess(langSettings.language));
+        await apiClient.changeTheme({ theme });
+        dispatch(changeThemeSuccess({ theme }));
     } catch (error) {
         dispatch(addErrorToast({ error }));
-        dispatch(getLanguageFailure());
+        dispatch(changeThemeFailure());
     }
 };
 
diff --git a/client/src/api/Api.js b/client/src/api/Api.js
index 06f40c6c..d984bbb8 100644
--- a/client/src/api/Api.js
+++ b/client/src/api/Api.js
@@ -1,8 +1,12 @@
 import axios from 'axios';
 
 import { getPathWithQueryString } from '../helpers/helpers';
-import { QUERY_LOGS_PAGE_LIMIT, HTML_PAGES, R_PATH_LAST_PART } from '../helpers/constants';
+import {
+    QUERY_LOGS_PAGE_LIMIT, HTML_PAGES, R_PATH_LAST_PART, THEMES,
+} from '../helpers/constants';
 import { BASE_URL } from '../../constants';
+import i18n from '../i18n';
+import { LANGUAGES } from '../helpers/twosky';
 
 class Api {
     baseUrl = BASE_URL;
@@ -224,21 +228,21 @@ class Api {
     }
 
     // Language
-    CURRENT_LANGUAGE = { path: 'i18n/current_language', method: 'GET' };
 
-    CHANGE_LANGUAGE = { path: 'i18n/change_language', method: 'POST' };
+    async changeLanguage(config) {
+        const profile = await this.getProfile();
+        profile.language = config.language;
 
-    getCurrentLanguage() {
-        const { path, method } = this.CURRENT_LANGUAGE;
-        return this.makeRequest(path, method);
+        return this.setProfile(profile);
     }
 
-    changeLanguage(config) {
-        const { path, method } = this.CHANGE_LANGUAGE;
-        const parameters = {
-            data: config,
-        };
-        return this.makeRequest(path, method, parameters);
+    // Theme
+
+    async changeTheme(config) {
+        const profile = await this.getProfile();
+        profile.theme = config.theme;
+
+        return this.setProfile(profile);
     }
 
     // DHCP
@@ -571,11 +575,24 @@ class Api {
     // Profile
     GET_PROFILE = { path: 'profile', method: 'GET' };
 
+    UPDATE_PROFILE = { path: 'profile/update', method: 'PUT' };
+
     getProfile() {
         const { path, method } = this.GET_PROFILE;
         return this.makeRequest(path, method);
     }
 
+    setProfile(data) {
+        const theme = data.theme ? data.theme : THEMES.auto;
+        const defaultLanguage = i18n.language ? i18n.language : LANGUAGES.en;
+        const language = data.language ? data.language : defaultLanguage;
+
+        const { path, method } = this.UPDATE_PROFILE;
+        const config = { data: { theme, language } };
+
+        return this.makeRequest(path, method, config);
+    }
+
     // DNS config
     GET_DNS_CONFIG = { path: 'dns_info', method: 'GET' };
 
diff --git a/client/src/components/App/index.css b/client/src/components/App/index.css
index fa8ca788..751a8e22 100644
--- a/client/src/components/App/index.css
+++ b/client/src/components/App/index.css
@@ -1,4 +1,26 @@
 :root {
+    --bgcolor: #f5f7fb;
+    --mcolor: #495057;
+    --scolor: rgba(74, 74, 74, 0.7);
+    --border-color: rgba(0, 40, 100, 0.12);
+    --header-bgcolor: #fff;
+    --card-bgcolor: #fff;
+    --card-border-color: rgba(0, 40, 100, 0.12);
+    --ctrl-bgcolor: #fff;
+    --ctrl-select-bgcolor: rgba(69, 79, 94, 0.12);
+    --ctrl-dropdown-color: #212529;
+    --ctrl-dropdown-bgcolor-focus: #f8f9fa;
+    --ctrl-dropdown-color-focus: #16181b;
+    --btn-success-bgcolor: #5eba00;
+    --form-disabled-bgcolor: #f8f9fa;
+    --form-disabled-color: #495057;
+    --rt-nodata-bgcolor: rgba(255,255,255,0.8);
+    --rt-nodata-color: rgba(0,0,0,0.5);
+    --modal-overlay-bgcolor: rgba(255, 255, 255, 0.75);
+    --logs__table-bgcolor: #fff;
+    --logs__row--blue-bgcolor: #e5effd;
+    --logs__row--white-bgcolor: #fff;
+    --detailed-info-color: #888888;
     --yellow-pale: rgba(247, 181, 0, 0.1);
     --green79: #67b279;
     --gray-a5: #a5a5a5;
@@ -8,6 +30,32 @@
     --font-size-disable-autozoom: 1rem;
 }
 
+[data-theme="dark"] {
+    --bgcolor: #131313;
+    --mcolor: #e6e6e6;
+    --scolor: #a5a5a5;
+    --header-bgcolor: #131313;
+    --border-color: #222;
+    --card-bgcolor: #1c1c1c;
+    --card-border-color: #3d3d3d;
+    --ctrl-bgcolor: #1c1c1c;
+    --ctrl-select-bgcolor: #3d3d3d;
+    --ctrl-dropdown-color: #fff;
+    --ctrl-dropdown-bgcolor-focus: #000;
+    --ctrl-dropdown-color-focus: #fff;
+    --btn-success-bgcolor: #67b279;
+    --form-disabled-bgcolor: #3d3d3d;
+    --form-disabled-color: #a5a5a5;
+    --logs__text-color: #f3f3f3;
+    --rt-nodata-bgcolor: #1c1c1c;
+    --rt-nodata-color: #fff;
+    --modal-overlay-bgcolor: #1c1c1c;
+    --logs__table-bgcolor: #3d3d3d;
+    --logs__row--blue-bgcolor: #467fcf;
+    --logs__row--white-bgcolor: #1c1c1c;
+    --detailed-info-color: #fff;
+}
+
 body {
     margin: 0;
     padding: 0;
diff --git a/client/src/components/App/index.js b/client/src/components/App/index.js
index 6d65ccb8..819bb0c6 100644
--- a/client/src/components/App/index.js
+++ b/client/src/components/App/index.js
@@ -20,8 +20,13 @@ import EncryptionTopline from '../ui/EncryptionTopline';
 import Icons from '../ui/Icons';
 import i18n from '../../i18n';
 import Loading from '../ui/Loading';
-import { FILTERS_URLS, MENU_URLS, SETTINGS_URLS } from '../../helpers/constants';
-import { getLogsUrlParams, setHtmlLangAttr } from '../../helpers/helpers';
+import {
+    FILTERS_URLS,
+    MENU_URLS,
+    SETTINGS_URLS,
+    THEMES,
+} from '../../helpers/constants';
+import { getLogsUrlParams, setHtmlLangAttr, setUITheme } from '../../helpers/helpers';
 import Header from '../Header';
 import { changeLanguage, getDnsStatus } from '../../actions';
 
@@ -109,6 +114,7 @@ const App = () => {
         isCoreRunning,
         isUpdateAvailable,
         processing,
+        theme,
     } = useSelector((state) => state.dashboard, shallowEqual);
 
     const { processing: processingEncryption } = useSelector((
@@ -138,6 +144,41 @@ const App = () => {
         setLanguage();
     }, [language]);
 
+    const handleAutoTheme = (e, accountTheme) => {
+        if (accountTheme !== THEMES.auto) {
+            return;
+        }
+
+        if (e.matches) {
+            setUITheme(THEMES.dark);
+        } else {
+            setUITheme(THEMES.light);
+        }
+    };
+
+    useEffect(() => {
+        if (theme !== THEMES.auto) {
+            setUITheme(theme);
+
+            return;
+        }
+
+        const colorSchemeMedia = window.matchMedia('(prefers-color-scheme: dark)');
+        const prefersDark = colorSchemeMedia.matches;
+        setUITheme(prefersDark ? THEMES.dark : THEMES.light);
+
+        if (colorSchemeMedia.addEventListener !== undefined) {
+            colorSchemeMedia.addEventListener('change', (e) => {
+                handleAutoTheme(e, theme);
+            });
+        } else {
+            // Deprecated addListener for older versions of Safari.
+            colorSchemeMedia.addListener((e) => {
+                handleAutoTheme(e, theme);
+            });
+        }
+    }, [theme]);
+
     const reloadPage = () => {
         window.location.reload();
     };
diff --git a/client/src/components/Header/Header.css b/client/src/components/Header/Header.css
index a5fe802e..c5412f7a 100644
--- a/client/src/components/Header/Header.css
+++ b/client/src/components/Header/Header.css
@@ -47,7 +47,7 @@
     width: 250px;
     height: 100vh;
     transition: transform 0.3s ease;
-    background-color: #fff;
+    background-color: var(--header-bgcolor);
     overflow-y: auto;
 }
 
diff --git a/client/src/components/Logs/Cells/IconTooltip.css b/client/src/components/Logs/Cells/IconTooltip.css
index 245c14d9..8f7eb453 100644
--- a/client/src/components/Logs/Cells/IconTooltip.css
+++ b/client/src/components/Logs/Cells/IconTooltip.css
@@ -4,7 +4,8 @@
     box-shadow: 2px 4px 8px rgba(0, 0, 0, 0.2);
     border-radius: 4px !important;
     pointer-events: auto !important;
-    background-color: var(--white);
+    background-color: var(--ctrl-bgcolor);
+    color: var(--scolor);
     z-index: 102;
     overflow-y: auto;
     max-height: 100%;
diff --git a/client/src/components/Logs/Filters/Form.js b/client/src/components/Logs/Filters/Form.js
index cf02ba5b..7b250ca5 100644
--- a/client/src/components/Logs/Filters/Form.js
+++ b/client/src/components/Logs/Filters/Form.js
@@ -155,7 +155,7 @@ const Form = (props) => {
                     name={FORM_NAMES.search}
                     component={renderFilterField}
                     type="text"
-                    className={classNames('form-control--search form-control--transparent', className)}
+                    className={classNames('form-control form-control--search form-control--transparent', className)}
                     placeholder={t('domain_or_client')}
                     tooltip={t('query_log_strict_search')}
                     onClearInputClick={onInputClear}
diff --git a/client/src/components/Logs/Logs.css b/client/src/components/Logs/Logs.css
index d365478b..358c2a6a 100644
--- a/client/src/components/Logs/Logs.css
+++ b/client/src/components/Logs/Logs.css
@@ -31,7 +31,7 @@
     overflow: hidden;
     font-size: 1rem;
     font-family: var(--font-family-sans-serif);
-    color: var(--gray-4d);
+    color: var(--logs__text-color);
     letter-spacing: 0;
     line-height: 1.5rem;
 }
@@ -48,7 +48,7 @@
 .detailed-info {
     font-size: 0.8rem;
     line-height: 1.4;
-    color: #888888;
+    color: var(--detailed-info-color);
 }
 
 .logs__text--link {
@@ -103,14 +103,12 @@
 }
 
 .form-control--search {
-    box-shadow: 0 1px 0 #ddd;
     padding: 0 2.5rem;
     height: 2.25rem;
     flex-grow: 1;
 }
 
 .form-control--transparent {
-    border: 0 solid transparent !important;
     background-color: transparent !important;
 }
 
@@ -174,10 +172,8 @@
     display: inline-flex;
     align-items: center;
     justify-content: center;
-
-    --size: 2.5rem;
-    width: var(--size);
-    height: var(--size);
+    width: 2.5rem;
+    height: 2.5rem;
     padding: 0;
     margin-left: 0.9375rem;
     background-color: transparent;
@@ -373,7 +369,7 @@
 
 /* QUERY_STATUS_COLORS */
 .logs__row--blue {
-    background-color: var(--blue);
+    background-color: var(--logs__row--blue-bgcolor);
 }
 
 .logs__row--green {
@@ -385,7 +381,7 @@
 }
 
 .logs__row--white {
-    background-color: var(--white);
+    background-color: var(--logs__row--white-bgcolor);
 }
 
 .logs__row--yellow {
@@ -393,8 +389,8 @@
 }
 
 .logs__no-data {
-    color: var(--gray-4d);
-    background-color: var(--white80);
+    color: var(--mcolor);
+    background-color: var(--logs__table-bgcolor);
     pointer-events: none;
     font-weight: 600;
     text-align: center;
@@ -407,7 +403,7 @@
 }
 
 .logs__table {
-    background-color: var(--white);
+    background-color: var(--logs__table-bgcolor);
     border: 0;
     border-radius: 8px;
     min-height: 43rem;
@@ -474,7 +470,7 @@
 
 .filteringRules__filter {
     font-style: italic;
-    font-weight: normal;
+    font-weight: 400;
     margin-bottom: 1rem;
 }
 
diff --git a/client/src/components/Settings/Clients/Form.js b/client/src/components/Settings/Clients/Form.js
index 35d9764d..f6b12d1c 100644
--- a/client/src/components/Settings/Clients/Form.js
+++ b/client/src/components/Settings/Clients/Form.js
@@ -11,12 +11,13 @@ import Select from 'react-select';
 import i18n from '../../../i18n';
 import Tabs from '../../ui/Tabs';
 import Examples from '../Dns/Upstream/Examples';
-import { toggleAllServices } from '../../../helpers/helpers';
+import { toggleAllServices, trimLinesAndRemoveEmpty } from '../../../helpers/helpers';
 import {
     renderInputField,
     renderGroupField,
     CheckboxField,
     renderServiceField,
+    renderTextareaField,
 } from '../../../helpers/form';
 import { validateClientId, validateRequiredValue } from '../../../helpers/validators';
 import { CLIENT_ID_LINK, FORM_NAME } from '../../../helpers/constants';
@@ -230,10 +231,11 @@ let Form = (props) => {
                 <Field
                     id="upstreams"
                     name="upstreams"
-                    component="textarea"
+                    component={renderTextareaField}
                     type="text"
                     className="form-control form-control--textarea mb-5"
                     placeholder={t('upstream_dns')}
+                    normalizeOnBlur={trimLinesAndRemoveEmpty}
                 />
                 <Examples />
             </div>,
diff --git a/client/src/components/Settings/Settings.css b/client/src/components/Settings/Settings.css
index 3fd560f9..ba6d2462 100644
--- a/client/src/components/Settings/Settings.css
+++ b/client/src/components/Settings/Settings.css
@@ -77,7 +77,7 @@
 .form__desc {
     margin-top: 10px;
     font-size: 13px;
-    color: rgba(74, 74, 74, 0.7);
+    color: var(--scolor);
 }
 
 .form__desc--top {
diff --git a/client/src/components/ui/Checkbox.css b/client/src/components/ui/Checkbox.css
index bab88c79..2a556fb0 100644
--- a/client/src/components/ui/Checkbox.css
+++ b/client/src/components/ui/Checkbox.css
@@ -107,5 +107,5 @@
 .checkbox__label-subtitle {
     display: block;
     line-height: 1.5;
-    color: rgba(74, 74, 74, 0.7);
+    color: var(--scolor);
 }
diff --git a/client/src/components/ui/Footer.css b/client/src/components/ui/Footer.css
index 66fbe5e2..fd0dca2b 100644
--- a/client/src/components/ui/Footer.css
+++ b/client/src/components/ui/Footer.css
@@ -18,6 +18,11 @@
     align-items: center;
 }
 
+.footer__column--theme {
+    min-width: 220px;
+    margin-bottom: 0;
+}
+
 .footer__column--language {
     min-width: 220px;
     margin-bottom: 0;
@@ -49,6 +54,11 @@
     }
 
     .footer__column--language {
+        min-width: initial;
+        margin-left: 20px;
+    }
+
+    .footer__column--theme {
         min-width: initial;
         margin-left: auto;
     }
diff --git a/client/src/components/ui/Footer.js b/client/src/components/ui/Footer.js
index 393e16fe..c1d1b40e 100644
--- a/client/src/components/ui/Footer.js
+++ b/client/src/components/ui/Footer.js
@@ -1,8 +1,9 @@
 import React from 'react';
 import { useTranslation } from 'react-i18next';
+import { useDispatch, useSelector } from 'react-redux';
 import classNames from 'classnames';
 
-import { REPOSITORY, PRIVACY_POLICY_LINK } from '../../helpers/constants';
+import { REPOSITORY, PRIVACY_POLICY_LINK, THEMES } from '../../helpers/constants';
 import { LANGUAGES } from '../../helpers/twosky';
 import i18n from '../../i18n';
 
@@ -10,6 +11,7 @@ import Version from './Version';
 import './Footer.css';
 import './Select.css';
 import { setHtmlLangAttr } from '../../helpers/helpers';
+import { changeTheme } from '../../actions';
 
 const linksData = [
     {
@@ -29,6 +31,11 @@ const linksData = [
 
 const Footer = () => {
     const { t } = useTranslation();
+    const dispatch = useDispatch();
+
+    const currentTheme = useSelector((state) => (state.dashboard ? state.dashboard.theme : 'auto'));
+    const profileName = useSelector((state) => (state.dashboard ? state.dashboard.name : ''));
+    const isLoggedIn = profileName !== '';
 
     const getYear = () => {
         const today = new Date();
@@ -41,6 +48,11 @@ const Footer = () => {
         setHtmlLangAttr(value);
     };
 
+    const onThemeChanged = (event) => {
+        const { value } = event.target;
+        dispatch(changeTheme(value));
+    };
+
     const renderCopyright = () => <div className="footer__column">
         <div className="footer__copyright">
             {t('copyright')} &copy; {getYear()}{' '}
@@ -58,6 +70,25 @@ const Footer = () => {
             {t(name)}
         </a>);
 
+    const renderThemeSelect = (currentTheme, isLoggedIn) => {
+        if (!isLoggedIn) {
+            return '';
+        }
+
+        return <select
+            className="form-control select select--theme"
+            value={currentTheme}
+            onChange={onThemeChanged}
+        >
+            {Object.values(THEMES)
+                .map((theme) => (
+                    <option key={theme} value={theme}>
+                        {t(`theme_${theme}`)}
+                    </option>
+                ))}
+        </select>;
+    };
+
     return (
         <>
             <footer className="footer">
@@ -66,6 +97,9 @@ const Footer = () => {
                         <div className="footer__column footer__column--links">
                             {renderLinks(linksData)}
                         </div>
+                        <div className="footer__column footer__column--theme">
+                            {renderThemeSelect(currentTheme, isLoggedIn)}
+                        </div>
                         <div className="footer__column footer__column--language">
                             <select
                                 className="form-control select select--language"
diff --git a/client/src/components/ui/Modal.css b/client/src/components/ui/Modal.css
index dc48bd78..b22b9709 100644
--- a/client/src/components/ui/Modal.css
+++ b/client/src/components/ui/Modal.css
@@ -11,6 +11,7 @@
 .ReactModal__Overlay--after-open {
     opacity: 1;
     transition: opacity 150ms ease-out;
+    background-color: var(--modal-overlay-bgcolor) !important;
 }
 
 .ReactModal__Content {
diff --git a/client/src/components/ui/ReactTable.css b/client/src/components/ui/ReactTable.css
index e8b1f4ca..820ba03f 100644
--- a/client/src/components/ui/ReactTable.css
+++ b/client/src/components/ui/ReactTable.css
@@ -13,6 +13,26 @@
     overflow: visible;
 }
 
+.ReactTable .rt-noData {
+    color: var(--rt-nodata-color);
+    background-color: var(--rt-nodata-bgcolor);
+}
+
+.ReactTable .-loading {
+    color: var(--rt-nodata-color);
+    background-color: var(--rt-nodata-bgcolor);
+}
+
+.ReactTable .-pagination input, .ReactTable .-pagination select {
+    color: var(--rt-nodata-color);
+    background-color: var(--rt-nodata-bgcolor);
+}
+
+[data-theme=dark] .ReactTable .-pagination .-btn {
+    color: var(--scolor);
+    background-color: var(--ctrl-bgcolor);
+}
+
 .rt-tr-group.logs__row--red {
     background-color: rgba(223, 56, 18, 0.05);
 }
diff --git a/client/src/components/ui/Select.css b/client/src/components/ui/Select.css
index ca428ff1..4150fb77 100644
--- a/client/src/components/ui/Select.css
+++ b/client/src/components/ui/Select.css
@@ -1,8 +1,25 @@
+.select.select--theme {
+    height: 45px;
+    padding: 0 32px 2px 11px;
+    outline: 0;
+    border-color: var(--ctrl-select-bgcolor);
+    background-image: url("./svg/chevron-down.svg");
+    background-repeat: no-repeat;
+    background-position: right 9px center;
+    background-size: 17px 20px;
+    appearance: none;
+    cursor: pointer;
+}
+
+.select--theme::-ms-expand {
+    opacity: 0;
+}
+
 .select.select--language {
     height: 45px;
     padding: 0 32px 2px 33px;
     outline: 0;
-    border-color: rgba(69, 79, 94, 0.12);
+    border-color: var(--ctrl-select-bgcolor);
     background-image: url("./svg/globe.svg"), url("./svg/chevron-down.svg");
     background-repeat: no-repeat, no-repeat;
     background-position: left 11px center, right 9px center;
@@ -16,8 +33,9 @@
 }
 
 .basic-multi-select .select__control {
-    border: 1px solid rgba(0, 40, 100, 0.12);
+    border: 1px solid var(--card-border-color);;
     border-radius: 3px;
+    background-color: var(--ctrl-bgcolor);
 }
 
 .basic-multi-select .select__control:hover {
@@ -36,4 +54,16 @@
 
 .basic-multi-select .select__menu {
     z-index: 3;
+    background-color: var(--ctrl-bgcolor);
+}
+
+[data-theme=dark] .basic-multi-select .select__option:hover,
+[data-theme=dark] .basic-multi-select .select__option--is-focused,
+[data-theme=dark] .basic-multi-select .select__option--is-focused:hover {
+    background-color: var(--ctrl-select-bgcolor);
+    color: var(--ctrl-dropdown-color);
+}
+
+[data-theme=dark] .select__multi-value__remove svg {
+    filter: invert(1);
 }
diff --git a/client/src/components/ui/Tabler.css b/client/src/components/ui/Tabler.css
index fac3d80a..6b6531ad 100644
--- a/client/src/components/ui/Tabler.css
+++ b/client/src/components/ui/Tabler.css
@@ -85,9 +85,9 @@ body {
     font-size: 0.9375rem;
     font-weight: 400;
     line-height: 1.5;
-    color: #495057;
+    color: var(--mcolor);
     text-align: left;
-    background-color: #f5f7fb;
+    background-color: var(--bgcolor);
 }
 
 [tabindex="-1"]:focus {
@@ -1943,10 +1943,10 @@ pre code {
     padding: 0.375rem 0.75rem;
     font-size: 0.9375rem;
     line-height: 1.6;
-    color: #495057;
-    background-color: #fff;
+    color: var(--mcolor);
+    background-color: var(--card-bgcolor);
     background-clip: padding-box;
-    border: 1px solid rgba(0, 40, 100, 0.12);
+    border: 1px solid var(--card-border-color);
     border-radius: 3px;
     transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
 }
@@ -1957,8 +1957,8 @@ pre code {
 }
 
 .form-control:focus {
-    color: #495057;
-    background-color: #fff;
+    color: var(--mcolor);
+    background-color: var(--ctrl-bgcolor);
     border-color: #1991eb;
     outline: 0;
     box-shadow: 0 0 0 2px rgba(70, 127, 207, 0.25);
@@ -1991,7 +1991,8 @@ pre code {
 
 .form-control:disabled,
 .form-control[readonly] {
-    background-color: #f8f9fa;
+    background-color: var(--form-disabled-bgcolor);
+    color: var(--form-disabled-color);
     opacity: 1;
 }
 
@@ -2580,7 +2581,7 @@ fieldset:disabled a.btn {
 
 .btn-success {
     color: #fff;
-    background-color: #5eba00;
+    background-color: var(--btn-success-bgcolor);
     border-color: #5eba00;
 }
 
@@ -3244,7 +3245,7 @@ tbody.collapse.show {
     color: #495057;
     text-align: left;
     list-style: none;
-    background-color: #fff;
+    background-color: var(--ctrl-bgcolor);
     background-clip: padding-box;
     border: 1px solid rgba(0, 40, 100, 0.12);
     border-radius: 3px;
@@ -3348,7 +3349,7 @@ tbody.collapse.show {
     padding: 0.25rem 1.5rem;
     clear: both;
     font-weight: 400;
-    color: #212529;
+    color: var(--ctrl-dropdown-color);
     text-align: inherit;
     white-space: nowrap;
     background-color: transparent;
@@ -3357,9 +3358,9 @@ tbody.collapse.show {
 
 .dropdown-item:hover,
 .dropdown-item:focus {
-    color: #16181b;
+    color: var(--ctrl-dropdown-color-focus);
     text-decoration: none;
-    background-color: #f8f9fa;
+    background-color: var(--ctrl-dropdown-bgcolor-focus);
 }
 
 .dropdown-item.active,
@@ -3794,11 +3795,11 @@ tbody.collapse.show {
     height: 2.375rem;
     padding: 0.5rem 1.75rem 0.5rem 0.75rem;
     line-height: 1.5;
-    color: #495057;
+    color: var(--mcolor);
     vertical-align: middle;
-    background: #fff url("data:image/svg+xml;base64,PHN2ZyB4bWxucz0naHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmcnIHZpZXdCb3g9JzAgMCAxMCA1Jz48cGF0aCBmaWxsPScjOTk5JyBkPSdNMCAwTDEwIDBMNSA1TDAgMCcvPjwvc3ZnPg==") no-repeat right 0.75rem center;
+    background: var(--card-bgcolor) url("data:image/svg+xml;base64,PHN2ZyB4bWxucz0naHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmcnIHZpZXdCb3g9JzAgMCAxMCA1Jz48cGF0aCBmaWxsPScjOTk5JyBkPSdNMCAwTDEwIDBMNSA1TDAgMCcvPjwvc3ZnPg==") no-repeat right 0.75rem center;
     background-size: 8px 10px;
-    border: 1px solid rgba(0, 40, 100, 0.12);
+    border: 1px solid var(--card-border-color);
     border-radius: 3px;
     -webkit-appearance: none;
     -moz-appearance: none;
@@ -4469,9 +4470,9 @@ tbody.collapse.show {
     flex-direction: column;
     min-width: 0;
     word-wrap: break-word;
-    background-color: #fff;
+    background-color: var(--card-bgcolor);
     background-clip: border-box;
-    border: 1px solid rgba(0, 40, 100, 0.12);
+    border: 1px solid var(--card-border-color);
     border-radius: 3px;
 }
 
@@ -5475,9 +5476,9 @@ button.close {
     flex-direction: column;
     width: 100%;
     pointer-events: auto;
-    background-color: #fff;
+    background-color: var(--card-bgcolor);
     background-clip: padding-box;
-    border: 1px solid rgba(0, 0, 0, 0.2);
+    border: 1px solid var(--card-border-color);
     border-radius: 3px;
     outline: 0;
 }
@@ -10268,8 +10269,8 @@ body.fixed-header .page {
 .header {
     padding-top: 0.75rem;
     padding-bottom: 0.75rem;
-    background: #fff;
-    border-bottom: 1px solid rgba(0, 40, 100, 0.12);
+    background: var(--header-bgcolor);
+    border-bottom: 1px solid var(--border-color);
 }
 
 body.fixed-header .header {
@@ -10325,6 +10326,10 @@ body.fixed-header .header {
     width: auto;
 }
 
+[data-theme=dark] .header-brand-img {
+    filter:invert(1);
+}
+
 .header-avatar {
     width: 2rem;
     height: 2rem;
@@ -10382,8 +10387,8 @@ body.fixed-header .header {
 }
 
 .footer {
-    background: #fff;
-    border-top: 1px solid rgba(0, 40, 100, 0.12);
+    background: var(--card-bgcolor);
+    border-top: 1px solid var(--card-border-color);
     font-size: 0.875rem;
     padding: 1.25rem 0;
     color: #9aa0ac;
@@ -13686,13 +13691,17 @@ Card alert
     content: "";
 }
 
+[data-theme=dark] .dropdown-menu-arrow:before {
+    border-bottom-color: var(--ctrl-bgcolor);
+}
+
 .dropdown-menu-arrow:after {
     position: absolute;
     top: -5px;
     left: 12px;
     display: inline-block;
     border-right: 5px solid transparent;
-    border-bottom: 5px solid #fff;
+    border-bottom: 5px solid var(--ctrl-bgcolor);
     border-left: 5px solid transparent;
     content: "";
 }
diff --git a/client/src/components/ui/Tooltip.css b/client/src/components/ui/Tooltip.css
index 6712f9d1..fe41623b 100644
--- a/client/src/components/ui/Tooltip.css
+++ b/client/src/components/ui/Tooltip.css
@@ -4,6 +4,11 @@
     box-shadow: 1px 1px 6px rgba(0, 0, 0, 0.2);
 }
 
+[data-theme=dark] .tooltip-container {
+    background-color: var(--ctrl-select-bgcolor);
+    color: var(--mcolor);
+}
+
 .tooltip-custom--narrow {
     max-width: 14rem;
 }
diff --git a/client/src/helpers/constants.js b/client/src/helpers/constants.js
index c13ab952..4f6803cb 100644
--- a/client/src/helpers/constants.js
+++ b/client/src/helpers/constants.js
@@ -227,6 +227,14 @@ export const BLOCKING_MODES = {
     custom_ip: 'custom_ip',
 };
 
+// Note that translation strings contain these modes (theme_CONSTANT)
+// i.e. theme_auto, theme_light.
+export const THEMES = {
+    auto: 'auto',
+    dark: 'dark',
+    light: 'light',
+};
+
 export const WHOIS_ICONS = {
     location: 'location',
     orgname: 'network',
diff --git a/client/src/helpers/helpers.js b/client/src/helpers/helpers.js
index af65589d..bc56fd42 100644
--- a/client/src/helpers/helpers.js
+++ b/client/src/helpers/helpers.js
@@ -670,6 +670,15 @@ export const setHtmlLangAttr = (language) => {
     window.document.documentElement.lang = language;
 };
 
+/**
+ * Sets UI theme.
+ *
+ * @param theme
+ */
+export const setUITheme = (theme) => {
+    document.body.dataset.theme = theme;
+};
+
 /**
  * @param values {object}
  * @returns {object}
diff --git a/client/src/reducers/dashboard.js b/client/src/reducers/dashboard.js
index 3709f10a..f201b2e0 100644
--- a/client/src/reducers/dashboard.js
+++ b/client/src/reducers/dashboard.js
@@ -112,14 +112,6 @@ const dashboard = handleActions(
             return newState;
         },
 
-        [actions.getLanguageSuccess]: (state, { payload }) => {
-            const newState = {
-                ...state,
-                language: payload,
-            };
-            return newState;
-        },
-
         [actions.getClientsRequest]: (state) => ({
             ...state,
             processingClients: true,
@@ -148,8 +140,13 @@ const dashboard = handleActions(
         [actions.getProfileSuccess]: (state, { payload }) => ({
             ...state,
             name: payload.name,
+            theme: payload.theme,
             processingProfile: false,
         }),
+        [actions.changeThemeSuccess]: (state, { payload }) => ({
+            ...state,
+            theme: payload.theme,
+        }),
     },
     {
         processing: true,
@@ -168,6 +165,7 @@ const dashboard = handleActions(
         autoClients: [],
         supportedTags: [],
         name: '',
+        theme: 'auto',
         checkUpdateFlag: false,
     },
 );
diff --git a/internal/dnsforward/dnsforward.go b/internal/dnsforward/dnsforward.go
index 5d1cce4a..8999845b 100644
--- a/internal/dnsforward/dnsforward.go
+++ b/internal/dnsforward/dnsforward.go
@@ -530,14 +530,14 @@ func validateBlockingMode(mode BlockingMode, blockingIPv4, blockingIPv6 net.IP)
 // prepareInternalProxy initializes the DNS proxy that is used for internal DNS
 // queries, such as public clients PTR resolving and updater hostname resolving.
 func (s *Server) prepareInternalProxy() (err error) {
+	srvConf := s.conf
 	conf := &proxy.Config{
 		CacheEnabled:   true,
 		CacheSizeBytes: 4096,
-		UpstreamConfig: s.conf.UpstreamConfig,
+		UpstreamConfig: srvConf.UpstreamConfig,
 		MaxGoroutines:  int(s.conf.MaxGoroutines),
 	}
 
-	srvConf := s.conf
 	setProxyUpstreamMode(
 		conf,
 		srvConf.AllServers,
diff --git a/internal/filtering/filter.go b/internal/filtering/filter.go
index 070ce73c..e64c2f12 100644
--- a/internal/filtering/filter.go
+++ b/internal/filtering/filter.go
@@ -2,6 +2,7 @@ package filtering
 
 import (
 	"bufio"
+	"bytes"
 	"fmt"
 	"hash/crc32"
 	"io"
@@ -12,6 +13,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/AdguardTeam/AdGuardHome/internal/aghalg"
 	"github.com/AdguardTeam/golibs/errors"
 	"github.com/AdguardTeam/golibs/log"
 	"github.com/AdguardTeam/golibs/stringutil"
@@ -97,14 +99,15 @@ func (d *DNSFilter) filterSetProperties(
 		filt.URL,
 	)
 
-	defer func(oldURL, oldName string, oldEnabled bool, oldUpdated time.Time) {
+	defer func(oldURL, oldName string, oldEnabled bool, oldUpdated time.Time, oldRulesCount int) {
 		if err != nil {
 			filt.URL = oldURL
 			filt.Name = oldName
 			filt.Enabled = oldEnabled
 			filt.LastUpdated = oldUpdated
+			filt.RulesCount = oldRulesCount
 		}
-	}(filt.URL, filt.Name, filt.Enabled, filt.LastUpdated)
+	}(filt.URL, filt.Name, filt.Enabled, filt.LastUpdated, filt.RulesCount)
 
 	filt.Name = newList.Name
 
@@ -134,8 +137,8 @@ func (d *DNSFilter) filterSetProperties(
 		// TODO(e.burkov):  The validation of the contents of the new URL is
 		// currently skipped if the rule list is disabled.  This makes it
 		// possible to set a bad rules source, but the validation should still
-		// kick in when the filter is enabled.  Consider making changing this
-		// behavior to be stricter.
+		// kick in when the filter is enabled.  Consider changing this behavior
+		// to be stricter.
 		filt.unload()
 	}
 
@@ -269,10 +272,10 @@ func (d *DNSFilter) periodicallyRefreshFilters() {
 // already going on.
 //
 // TODO(e.burkov):  Get rid of the concurrency pattern which requires the
-// sync.Mutex.TryLock.
+// [sync.Mutex.TryLock].
 func (d *DNSFilter) tryRefreshFilters(block, allow, force bool) (updated int, isNetworkErr, ok bool) {
 	if ok = d.refreshLock.TryLock(); !ok {
-		return 0, false, ok
+		return 0, false, false
 	}
 	defer d.refreshLock.Unlock()
 
@@ -427,52 +430,124 @@ func (d *DNSFilter) refreshFiltersIntl(block, allow, force bool) (int, bool) {
 	return updNum, false
 }
 
-// Allows printable UTF-8 text with CR, LF, TAB characters
-func isPrintableText(data []byte, len int) bool {
-	for i := 0; i < len; i++ {
-		c := data[i]
+// isPrintableText returns true if data is printable UTF-8 text with CR, LF, TAB
+// characters.
+//
+// TODO(e.burkov):  Investigate the purpose of this and improve the
+// implementation.  Perhaps, use something from the unicode package.
+func isPrintableText(data string) (ok bool) {
+	for _, c := range []byte(data) {
 		if (c >= ' ' && c != 0x7f) || c == '\n' || c == '\r' || c == '\t' {
 			continue
 		}
+
 		return false
 	}
+
 	return true
 }
 
-// A helper function that parses filter contents and returns a number of rules and a filter name (if there's any)
-func (d *DNSFilter) parseFilterContents(file io.Reader) (int, uint32, string) {
-	rulesCount := 0
-	name := ""
-	seenTitle := false
-	r := bufio.NewReader(file)
-	checksum := uint32(0)
+// scanLinesWithBreak is essentially a [bufio.ScanLines] which keeps trailing
+// line breaks.
+func scanLinesWithBreak(data []byte, atEOF bool) (advance int, token []byte, err error) {
+	if atEOF && len(data) == 0 {
+		return 0, nil, nil
+	}
 
-	for {
-		line, err := r.ReadString('\n')
-		checksum = crc32.Update(checksum, crc32.IEEETable, []byte(line))
+	if i := bytes.IndexByte(data, '\n'); i >= 0 {
+		return i + 1, data[0 : i+1], nil
+	}
 
-		line = strings.TrimSpace(line)
-		if len(line) == 0 {
-			//
-		} else if line[0] == '!' {
-			m := d.filterTitleRegexp.FindAllStringSubmatch(line, -1)
-			if len(m) > 0 && len(m[0]) >= 2 && !seenTitle {
-				name = m[0][1]
-				seenTitle = true
-			}
+	if atEOF {
+		return len(data), data, nil
+	}
 
-		} else if line[0] == '#' {
-			//
-		} else {
-			rulesCount++
+	// Request more data.
+	return 0, nil, nil
+}
+
+// parseFilter copies filter's content from src to dst and returns the number of
+// rules, name, number of bytes written, checksum, and title of the parsed list.
+// dst must not be nil.
+func (d *DNSFilter) parseFilter(
+	src io.Reader,
+	dst io.Writer,
+) (rulesNum, written int, checksum uint32, title string, err error) {
+	scanner := bufio.NewScanner(src)
+	scanner.Split(scanLinesWithBreak)
+
+	titleFound := false
+	for n := 0; scanner.Scan(); written += n {
+		line := scanner.Text()
+		var isRule bool
+		var likelyTitle string
+		isRule, likelyTitle, err = d.parseFilterLine(line, !titleFound, written == 0)
+		if err != nil {
+			return 0, written, 0, "", err
 		}
 
+		if isRule {
+			rulesNum++
+		} else if likelyTitle != "" {
+			title, titleFound = likelyTitle, true
+		}
+
+		checksum = crc32.Update(checksum, crc32.IEEETable, []byte(line))
+
+		n, err = dst.Write([]byte(line))
 		if err != nil {
-			break
+			return 0, written, 0, "", fmt.Errorf("writing filter line: %w", err)
 		}
 	}
 
-	return rulesCount, checksum, name
+	if err = scanner.Err(); err != nil {
+		return 0, written, 0, "", fmt.Errorf("scanning filter contents: %w", err)
+	}
+
+	return rulesNum, written, checksum, title, nil
+}
+
+// parseFilterLine returns true if the passed line is a rule.  line is
+// considered a rule if it's not a comment and contains no title.
+func (d *DNSFilter) parseFilterLine(
+	line string,
+	lookForTitle bool,
+	testHTML bool,
+) (isRule bool, title string, err error) {
+	if !isPrintableText(line) {
+		return false, "", errors.Error("filter contains non-printable characters")
+	}
+
+	line = strings.TrimSpace(line)
+	if line == "" || line[0] == '#' {
+		return false, "", nil
+	}
+
+	if testHTML && isHTML(line) {
+		return false, "", errors.Error("data is HTML, not plain text")
+	}
+
+	if line[0] == '!' && lookForTitle {
+		match := d.filterTitleRegexp.FindStringSubmatch(line)
+		if len(match) > 1 {
+			title = match[1]
+		}
+
+		return false, title, nil
+	}
+
+	return true, "", nil
+}
+
+// isHTML returns true if the line contains HTML tags instead of plain text.
+// line shouldn have no leading space symbols.
+//
+// TODO(ameshkov):  It actually gives too much false-positives.  Perhaps, just
+// check if trimmed string begins with angle bracket.
+func isHTML(line string) (ok bool) {
+	line = strings.ToLower(line)
+
+	return strings.HasPrefix(line, "<html") || strings.HasPrefix(line, "<!doctype")
 }
 
 // Perform upgrade on a filter and update LastUpdated value
@@ -485,57 +560,10 @@ func (d *DNSFilter) update(filter *FilterYAML) (bool, error) {
 			log.Error("os.Chtimes(): %v", e)
 		}
 	}
+
 	return b, err
 }
 
-func (d *DNSFilter) read(reader io.Reader, tmpFile *os.File, filter *FilterYAML) (int, error) {
-	htmlTest := true
-	firstChunk := make([]byte, 4*1024)
-	firstChunkLen := 0
-	buf := make([]byte, 64*1024)
-	total := 0
-	for {
-		n, err := reader.Read(buf)
-		total += n
-
-		if htmlTest {
-			num := len(firstChunk) - firstChunkLen
-			if n < num {
-				num = n
-			}
-			copied := copy(firstChunk[firstChunkLen:], buf[:num])
-			firstChunkLen += copied
-
-			if firstChunkLen == len(firstChunk) || err == io.EOF {
-				if !isPrintableText(firstChunk, firstChunkLen) {
-					return total, fmt.Errorf("data contains non-printable characters")
-				}
-
-				s := strings.ToLower(string(firstChunk))
-				if strings.Contains(s, "<html") || strings.Contains(s, "<!doctype") {
-					return total, fmt.Errorf("data is HTML, not plain text")
-				}
-
-				htmlTest = false
-				firstChunk = nil
-			}
-		}
-
-		_, err2 := tmpFile.Write(buf[:n])
-		if err2 != nil {
-			return total, err2
-		}
-
-		if err == io.EOF {
-			return total, nil
-		}
-		if err != nil {
-			log.Printf("Couldn't fetch filter contents from URL %s, skipping: %s", filter.URL, err)
-			return total, err
-		}
-	}
-}
-
 // finalizeUpdate closes and gets rid of temporary file f with filter's content
 // according to updated.  It also saves new values of flt's name, rules number
 // and checksum if sucсeeded.
@@ -552,7 +580,8 @@ func (d *DNSFilter) finalizeUpdate(
 	// Close the file before renaming it because it's required on Windows.
 	//
 	// See https://github.com/adguardTeam/adGuardHome/issues/1553.
-	if err = file.Close(); err != nil {
+	err = file.Close()
+	if err != nil {
 		return fmt.Errorf("closing temporary file: %w", err)
 	}
 
@@ -564,38 +593,18 @@ func (d *DNSFilter) finalizeUpdate(
 
 	log.Printf("saving filter %d contents to: %s", flt.ID, flt.Path(d.DataDir))
 
-	if err = os.Rename(tmpFileName, flt.Path(d.DataDir)); err != nil {
+	// Don't use renamio or maybe packages, since those will require loading the
+	// whole filter content to the memory on Windows.
+	err = os.Rename(tmpFileName, flt.Path(d.DataDir))
+	if err != nil {
 		return errors.WithDeferred(err, os.Remove(tmpFileName))
 	}
 
-	flt.Name = stringutil.Coalesce(flt.Name, name)
-	flt.checksum = cs
-	flt.RulesCount = rnum
+	flt.Name, flt.checksum, flt.RulesCount = aghalg.Coalesce(flt.Name, name), cs, rnum
 
 	return nil
 }
 
-// processUpdate copies filter's content from src to dst and returns the name,
-// rules number, and checksum for it.  It also returns the number of bytes read
-// from src.
-func (d *DNSFilter) processUpdate(
-	src io.Reader,
-	dst *os.File,
-	flt *FilterYAML,
-) (name string, rnum int, cs uint32, n int, err error) {
-	if n, err = d.read(src, dst, flt); err != nil {
-		return "", 0, 0, 0, err
-	}
-
-	if _, err = dst.Seek(0, io.SeekStart); err != nil {
-		return "", 0, 0, 0, err
-	}
-
-	rnum, cs, name = d.parseFilterContents(dst)
-
-	return name, rnum, cs, n, nil
-}
-
 // updateIntl updates the flt rewriting it's actual file.  It returns true if
 // the actual update has been performed.
 func (d *DNSFilter) updateIntl(flt *FilterYAML) (ok bool, err error) {
@@ -612,31 +621,21 @@ func (d *DNSFilter) updateIntl(flt *FilterYAML) (ok bool, err error) {
 	}
 	defer func() {
 		err = errors.WithDeferred(err, d.finalizeUpdate(tmpFile, flt, ok, name, rnum, cs))
-		ok = ok && err == nil
-		if ok {
+		if ok && err == nil {
 			log.Printf("updated filter %d: %d bytes, %d rules", flt.ID, n, rnum)
 		}
 	}()
 
-	// Change the default 0o600 permission to something more acceptable by
-	// end users.
+	// Change the default 0o600 permission to something more acceptable by end
+	// users.
 	//
 	// See https://github.com/AdguardTeam/AdGuardHome/issues/3198.
 	if err = tmpFile.Chmod(0o644); err != nil {
 		return false, fmt.Errorf("changing file mode: %w", err)
 	}
 
-	var r io.Reader
-	if filepath.IsAbs(flt.URL) {
-		var file io.ReadCloser
-		file, err = os.Open(flt.URL)
-		if err != nil {
-			return false, fmt.Errorf("open file: %w", err)
-		}
-		defer func() { err = errors.WithDeferred(err, file.Close()) }()
-
-		r = file
-	} else {
+	var rc io.ReadCloser
+	if !filepath.IsAbs(flt.URL) {
 		var resp *http.Response
 		resp, err = d.HTTPClient.Get(flt.URL)
 		if err != nil {
@@ -649,24 +648,30 @@ func (d *DNSFilter) updateIntl(flt *FilterYAML) (ok bool, err error) {
 		if resp.StatusCode != http.StatusOK {
 			log.Printf("got status code %d from %s, skip", resp.StatusCode, flt.URL)
 
-			return false, fmt.Errorf("got status code != 200: %d", resp.StatusCode)
+			return false, fmt.Errorf("got status code %d, want %d", resp.StatusCode, http.StatusOK)
 		}
 
-		r = resp.Body
+		rc = resp.Body
+	} else {
+		rc, err = os.Open(flt.URL)
+		if err != nil {
+			return false, fmt.Errorf("open file: %w", err)
+		}
+		defer func() { err = errors.WithDeferred(err, rc.Close()) }()
 	}
 
-	name, rnum, cs, n, err = d.processUpdate(r, tmpFile, flt)
+	rnum, n, cs, name, err = d.parseFilter(rc, tmpFile)
 
-	return cs != flt.checksum, err
+	return cs != flt.checksum && err == nil, err
 }
 
 // loads filter contents from the file in dataDir
-func (d *DNSFilter) load(filter *FilterYAML) (err error) {
-	filterFilePath := filter.Path(d.DataDir)
+func (d *DNSFilter) load(flt *FilterYAML) (err error) {
+	fileName := flt.Path(d.DataDir)
 
-	log.Tracef("filtering: loading filter %d from %s", filter.ID, filterFilePath)
+	log.Debug("filtering: loading filter %d from %s", flt.ID, fileName)
 
-	file, err := os.Open(filterFilePath)
+	file, err := os.Open(fileName)
 	if errors.Is(err, os.ErrNotExist) {
 		// Do nothing, file doesn't exist.
 		return nil
@@ -680,13 +685,14 @@ func (d *DNSFilter) load(filter *FilterYAML) (err error) {
 		return fmt.Errorf("getting filter file stat: %w", err)
 	}
 
-	log.Tracef("filtering: File %s, id %d, length %d", filterFilePath, filter.ID, st.Size())
+	log.Debug("filtering: file %s, id %d, length %d", fileName, flt.ID, st.Size())
 
-	rulesCount, checksum, _ := d.parseFilterContents(file)
+	rulesCount, _, checksum, _, err := d.parseFilter(file, io.Discard)
+	if err != nil {
+		return fmt.Errorf("parsing filter file: %w", err)
+	}
 
-	filter.RulesCount = rulesCount
-	filter.checksum = checksum
-	filter.LastUpdated = st.ModTime()
+	flt.RulesCount, flt.checksum, flt.LastUpdated = rulesCount, checksum, st.ModTime()
 
 	return nil
 }
diff --git a/internal/filtering/filter_test.go b/internal/filtering/filter_test.go
index 81a7929a..53e846fc 100644
--- a/internal/filtering/filter_test.go
+++ b/internal/filtering/filter_test.go
@@ -4,33 +4,23 @@ import (
 	"io/fs"
 	"net"
 	"net/http"
-	"net/netip"
 	"net/url"
 	"os"
 	"path/filepath"
 	"testing"
 	"time"
 
-	"github.com/AdguardTeam/golibs/netutil"
+	"github.com/AdguardTeam/AdGuardHome/internal/aghhttp"
 	"github.com/AdguardTeam/golibs/testutil"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
-// serveFiltersLocally is a helper that concurrently listens on a free port to
-// respond with fltContent.  It also gracefully closes the listener when the
-// test under t finishes.
-func serveFiltersLocally(t *testing.T, fltContent []byte) (ipp netip.AddrPort) {
+// serveHTTPLocally starts a new HTTP server, that handles its index with h.  It
+// also gracefully closes the listener when the test under t finishes.
+func serveHTTPLocally(t *testing.T, h http.Handler) (urlStr string) {
 	t.Helper()
 
-	h := http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
-		pt := testutil.PanicT{}
-
-		n, werr := w.Write(fltContent)
-		require.NoError(pt, werr)
-		require.Equal(pt, len(fltContent), n)
-	})
-
 	l, err := net.Listen("tcp", ":0")
 	require.NoError(t, err)
 
@@ -38,9 +28,26 @@ func serveFiltersLocally(t *testing.T, fltContent []byte) (ipp netip.AddrPort) {
 	testutil.CleanupAndRequireSuccess(t, l.Close)
 
 	addr := l.Addr()
-	require.IsType(t, new(net.TCPAddr), addr)
+	require.IsType(t, (*net.TCPAddr)(nil), addr)
 
-	return netip.AddrPortFrom(netutil.IPv4Localhost(), uint16(addr.(*net.TCPAddr).Port))
+	return (&url.URL{
+		Scheme: aghhttp.SchemeHTTP,
+		Host:   addr.String(),
+	}).String()
+}
+
+// serveFiltersLocally is a helper that concurrently listens on a free port to
+// respond with fltContent.
+func serveFiltersLocally(t *testing.T, fltContent []byte) (urlStr string) {
+	t.Helper()
+
+	return serveHTTPLocally(t, http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		pt := testutil.PanicT{}
+
+		n, werr := w.Write(fltContent)
+		require.NoError(pt, werr)
+		require.Equal(pt, len(fltContent), n)
+	}))
 }
 
 func TestFilters(t *testing.T) {
@@ -65,10 +72,7 @@ func TestFilters(t *testing.T) {
 	require.NoError(t, err)
 
 	f := &FilterYAML{
-		URL: (&url.URL{
-			Scheme: "http",
-			Host:   addr.String(),
-		}).String(),
+		URL: addr,
 	}
 
 	updateAndAssert := func(t *testing.T, want require.BoolAssertionFunc, wantRulesCount int) {
@@ -103,11 +107,7 @@ func TestFilters(t *testing.T) {
 		anotherContent := []byte(`||example.com^`)
 		oldURL := f.URL
 
-		ipp := serveFiltersLocally(t, anotherContent)
-		f.URL = (&url.URL{
-			Scheme: "http",
-			Host:   ipp.String(),
-		}).String()
+		f.URL = serveFiltersLocally(t, anotherContent)
 		t.Cleanup(func() { f.URL = oldURL })
 
 		updateAndAssert(t, require.True, 1)
diff --git a/internal/filtering/filtering.go b/internal/filtering/filtering.go
index db6e1b17..fd5953e3 100644
--- a/internal/filtering/filtering.go
+++ b/internal/filtering/filtering.go
@@ -190,6 +190,8 @@ type DNSFilter struct {
 
 	// filterTitleRegexp is the regular expression to retrieve a name of a
 	// filter list.
+	//
+	// TODO(e.burkov):  Don't use regexp for such a simple text processing task.
 	filterTitleRegexp *regexp.Regexp
 
 	hostCheckers []hostChecker
diff --git a/internal/filtering/http_test.go b/internal/filtering/http_test.go
index 987b8a2c..df09c3f9 100644
--- a/internal/filtering/http_test.go
+++ b/internal/filtering/http_test.go
@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"net/http"
 	"net/http/httptest"
-	"net/url"
 	"testing"
 	"time"
 
@@ -30,11 +29,7 @@ func TestDNSFilter_handleFilteringSetURL(t *testing.T) {
 		endpoint: &badRulesEndpoint,
 		content:  []byte(`<html></html>`),
 	}} {
-		ipp := serveFiltersLocally(t, rulesSource.content)
-		*rulesSource.endpoint = (&url.URL{
-			Scheme: "http",
-			Host:   ipp.String(),
-		}).String()
+		*rulesSource.endpoint = serveFiltersLocally(t, rulesSource.content)
 	}
 
 	testCases := []struct {
diff --git a/internal/home/config.go b/internal/home/config.go
index ddefd61e..dd2f0730 100644
--- a/internal/home/config.go
+++ b/internal/home/config.go
@@ -106,6 +106,8 @@ type configuration struct {
 	ProxyURL string `yaml:"http_proxy"`
 	// Language is a two-letter ISO 639-1 language code.
 	Language string `yaml:"language"`
+	// Theme is a UI theme for current user.
+	Theme Theme `yaml:"theme"`
 	// DebugPProf defines if the profiling HTTP handler will listen on :6060.
 	DebugPProf bool `yaml:"debug_pprof"`
 
@@ -322,6 +324,7 @@ var config = &configuration{
 	},
 	OSConfig:      &osConfig{},
 	SchemaVersion: currentSchemaVersion,
+	Theme:         ThemeAuto,
 }
 
 // getConfigFilename returns path to the current config file
diff --git a/internal/home/control.go b/internal/home/control.go
index f9e7d4d2..ef67a7f7 100644
--- a/internal/home/control.go
+++ b/internal/home/control.go
@@ -149,19 +149,6 @@ func handleStatus(w http.ResponseWriter, r *http.Request) {
 	_ = aghhttp.WriteJSONResponse(w, r, resp)
 }
 
-type profileJSON struct {
-	Name string `json:"name"`
-}
-
-func handleGetProfile(w http.ResponseWriter, r *http.Request) {
-	u := Context.auth.getCurrentUser(r)
-	resp := &profileJSON{
-		Name: u.Name,
-	}
-
-	_ = aghhttp.WriteJSONResponse(w, r, resp)
-}
-
 // ------------------------
 // registration of handlers
 // ------------------------
@@ -172,6 +159,7 @@ func registerControlHandlers() {
 	Context.mux.HandleFunc("/control/version.json", postInstall(optionalAuth(handleGetVersionJSON)))
 	httpRegister(http.MethodPost, "/control/update", handleUpdate)
 	httpRegister(http.MethodGet, "/control/profile", handleGetProfile)
+	httpRegister(http.MethodPut, "/control/profile/update", handlePutProfile)
 
 	// No auth is necessary for DoH/DoT configurations
 	Context.mux.HandleFunc("/apple/doh.mobileconfig", postInstall(handleMobileConfigDoH))
diff --git a/internal/home/controlupdate.go b/internal/home/controlupdate.go
index ef4f0659..5718bfaa 100644
--- a/internal/home/controlupdate.go
+++ b/internal/home/controlupdate.go
@@ -123,7 +123,7 @@ func handleUpdate(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	err = Context.updater.Update()
+	err = Context.updater.Update(false)
 	if err != nil {
 		aghhttp.Error(r, w, http.StatusInternalServerError, "%s", err)
 
diff --git a/internal/home/dns.go b/internal/home/dns.go
index 1980b252..9d073d7b 100644
--- a/internal/home/dns.go
+++ b/internal/home/dns.go
@@ -9,7 +9,9 @@ import (
 	"path/filepath"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/aghalg"
+	"github.com/AdguardTeam/AdGuardHome/internal/aghhttp"
 	"github.com/AdguardTeam/AdGuardHome/internal/aghnet"
+	"github.com/AdguardTeam/AdGuardHome/internal/dhcpd"
 	"github.com/AdguardTeam/AdGuardHome/internal/dnsforward"
 	"github.com/AdguardTeam/AdGuardHome/internal/filtering"
 	"github.com/AdguardTeam/AdGuardHome/internal/querylog"
@@ -39,17 +41,13 @@ func onConfigModified() {
 	}
 }
 
-// initDNSServer creates an instance of the dnsforward.Server
-// Please note that we must do it even if we don't start it
-// so that we had access to the query log and the stats
-func initDNSServer() (err error) {
+// initDNS updates all the fields of the [Context] needed to initialize the DNS
+// server and initializes it at last.  It also must not be called unless
+// [config] and [Context] are initialized.
+func initDNS() (err error) {
 	baseDir := Context.getDataDir()
 
-	var anonFunc aghnet.IPMutFunc
-	if config.DNS.AnonymizeClientIP {
-		anonFunc = querylog.AnonymizeIP
-	}
-	anonymizer := aghnet.NewIPMut(anonFunc)
+	anonymizer := config.anonymizer()
 
 	statsConf := stats.Config{
 		Filename:       filepath.Join(baseDir, "stats.db"),
@@ -82,34 +80,46 @@ func initDNSServer() (err error) {
 		return err
 	}
 
-	var privateNets netutil.SubnetSet
-	switch len(config.DNS.PrivateNets) {
-	case 0:
-		// Use an optimized locally-served matcher.
-		privateNets = netutil.SubnetSetFunc(netutil.IsLocallyServed)
-	case 1:
-		privateNets, err = netutil.ParseSubnet(config.DNS.PrivateNets[0])
-		if err != nil {
-			return fmt.Errorf("preparing the set of private subnets: %w", err)
-		}
-	default:
-		var nets []*net.IPNet
-		nets, err = netutil.ParseSubnets(config.DNS.PrivateNets...)
-		if err != nil {
-			return fmt.Errorf("preparing the set of private subnets: %w", err)
-		}
+	tlsConf := &tlsConfigSettings{}
+	Context.tls.WriteDiskConfig(tlsConf)
 
-		privateNets = netutil.SliceSubnetSet(nets)
+	return initDNSServer(
+		Context.filters,
+		Context.stats,
+		Context.queryLog,
+		Context.dhcpServer,
+		anonymizer,
+		httpRegister,
+		tlsConf,
+	)
+}
+
+// initDNSServer initializes the [context.dnsServer].  To only use the internal
+// proxy, none of the arguments are required, but tlsConf still must not be nil,
+// in other cases all the arguments also must not be nil.  It also must not be
+// called unless [config] and [Context] are initialized.
+func initDNSServer(
+	filters *filtering.DNSFilter,
+	sts stats.Interface,
+	qlog querylog.QueryLog,
+	dhcpSrv dhcpd.Interface,
+	anonymizer *aghnet.IPMut,
+	httpReg aghhttp.RegisterFunc,
+	tlsConf *tlsConfigSettings,
+) (err error) {
+	privateNets, err := parseSubnetSet(config.DNS.PrivateNets)
+	if err != nil {
+		return fmt.Errorf("preparing set of private subnets: %w", err)
 	}
 
 	p := dnsforward.DNSCreateParams{
-		DNSFilter:   Context.filters,
-		Stats:       Context.stats,
-		QueryLog:    Context.queryLog,
+		DNSFilter:   filters,
+		Stats:       sts,
+		QueryLog:    qlog,
 		PrivateNets: privateNets,
 		Anonymizer:  anonymizer,
 		LocalDomain: config.DHCP.LocalDomainName,
-		DHCPServer:  Context.dhcpServer,
+		DHCPServer:  dhcpSrv,
 	}
 
 	Context.dnsServer, err = dnsforward.NewServer(p)
@@ -120,15 +130,15 @@ func initDNSServer() (err error) {
 	}
 
 	Context.clients.dnsServer = Context.dnsServer
-	var dnsConfig dnsforward.ServerConfig
-	dnsConfig, err = generateServerConfig()
+
+	dnsConf, err := generateServerConfig(tlsConf, httpReg)
 	if err != nil {
 		closeDNSServer()
 
 		return fmt.Errorf("generateServerConfig: %w", err)
 	}
 
-	err = Context.dnsServer.Prepare(&dnsConfig)
+	err = Context.dnsServer.Prepare(&dnsConf)
 	if err != nil {
 		closeDNSServer()
 
@@ -146,6 +156,32 @@ func initDNSServer() (err error) {
 	return nil
 }
 
+// parseSubnetSet parses a slice of subnets.  If the slice is empty, it returns
+// a subnet set that matches all locally served networks, see
+// [netutil.IsLocallyServed].
+func parseSubnetSet(nets []string) (s netutil.SubnetSet, err error) {
+	switch len(nets) {
+	case 0:
+		// Use an optimized function-based matcher.
+		return netutil.SubnetSetFunc(netutil.IsLocallyServed), nil
+	case 1:
+		s, err = netutil.ParseSubnet(nets[0])
+		if err != nil {
+			return nil, err
+		}
+
+		return s, nil
+	default:
+		var nets []*net.IPNet
+		nets, err = netutil.ParseSubnets(config.DNS.PrivateNets...)
+		if err != nil {
+			return nil, err
+		}
+
+		return netutil.SliceSubnetSet(nets), nil
+	}
+}
+
 func isRunning() bool {
 	return Context.dnsServer != nil && Context.dnsServer.IsRunning()
 }
@@ -193,7 +229,10 @@ func ipsToUDPAddrs(ips []netip.Addr, port int) (udpAddrs []*net.UDPAddr) {
 	return udpAddrs
 }
 
-func generateServerConfig() (newConf dnsforward.ServerConfig, err error) {
+func generateServerConfig(
+	tlsConf *tlsConfigSettings,
+	httpReg aghhttp.RegisterFunc,
+) (newConf dnsforward.ServerConfig, err error) {
 	dnsConf := config.DNS
 	hosts := aghalg.CoalesceSlice(dnsConf.BindHosts, []netip.Addr{netutil.IPv4Localhost()})
 	newConf = dnsforward.ServerConfig{
@@ -201,12 +240,10 @@ func generateServerConfig() (newConf dnsforward.ServerConfig, err error) {
 		TCPListenAddrs:  ipsToTCPAddrs(hosts, dnsConf.Port),
 		FilteringConfig: dnsConf.FilteringConfig,
 		ConfigModified:  onConfigModified,
-		HTTPRegister:    httpRegister,
+		HTTPRegister:    httpReg,
 		OnDNSRequest:    onDNSRequest,
 	}
 
-	tlsConf := tlsConfigSettings{}
-	Context.tls.WriteDiskConfig(&tlsConf)
 	if tlsConf.Enabled {
 		newConf.TLSConfig = tlsConf.TLSConfig
 		newConf.TLSConfig.ServerName = tlsConf.ServerName
@@ -224,7 +261,7 @@ func generateServerConfig() (newConf dnsforward.ServerConfig, err error) {
 		}
 
 		if tlsConf.PortDNSCrypt != 0 {
-			newConf.DNSCryptConfig, err = newDNSCrypt(hosts, tlsConf)
+			newConf.DNSCryptConfig, err = newDNSCrypt(hosts, *tlsConf)
 			if err != nil {
 				// Don't wrap the error, because it's already
 				// wrapped by newDNSCrypt.
@@ -413,7 +450,11 @@ func startDNSServer() error {
 
 func reconfigureDNSServer() (err error) {
 	var newConf dnsforward.ServerConfig
-	newConf, err = generateServerConfig()
+
+	tlsConf := &tlsConfigSettings{}
+	Context.tls.WriteDiskConfig(tlsConf)
+
+	newConf, err = generateServerConfig(tlsConf, httpRegister)
 	if err != nil {
 		return fmt.Errorf("generating forwarding dns server config: %w", err)
 	}
diff --git a/internal/home/home.go b/internal/home/home.go
index 3085d66c..ce464060 100644
--- a/internal/home/home.go
+++ b/internal/home/home.go
@@ -455,6 +455,10 @@ func run(opts options, clientBuildFS fs.FS) {
 	err = setupConfig(opts)
 	fatalOnError(err)
 
+	// TODO(e.burkov):  This could be made earlier, probably as the option's
+	// effect.
+	cmdlineUpdate(opts)
+
 	if !Context.firstRun {
 		// Save the updated config
 		err = config.write()
@@ -522,7 +526,7 @@ func run(opts options, clientBuildFS fs.FS) {
 	fatalOnError(err)
 
 	if !Context.firstRun {
-		err = initDNSServer()
+		err = initDNS()
 		fatalOnError(err)
 
 		Context.tls.start()
@@ -543,20 +547,24 @@ func run(opts options, clientBuildFS fs.FS) {
 		}
 	}
 
-	// TODO(a.garipov): This could be made much earlier and could be done on
-	// the first run as well, but to achieve this we need to bypass requests
-	// over dnsforward resolver.
-	cmdlineUpdate(opts)
-
 	Context.web.Start()
 
 	// wait indefinitely for other go-routines to complete their job
 	select {}
 }
 
+func (c *configuration) anonymizer() (ipmut *aghnet.IPMut) {
+	var anonFunc aghnet.IPMutFunc
+	if c.DNS.AnonymizeClientIP {
+		anonFunc = querylog.AnonymizeIP
+	}
+
+	return aghnet.NewIPMut(anonFunc)
+}
+
 // startMods initializes and starts the DNS server after installation.
-func startMods() error {
-	err := initDNSServer()
+func startMods() (err error) {
+	err = initDNS()
 	if err != nil {
 		return err
 	}
@@ -927,8 +935,8 @@ func getHTTPProxy(_ *http.Request) (*url.URL, error) {
 
 // jsonError is a generic JSON error response.
 //
-// TODO(a.garipov): Merge together with the implementations in .../dhcpd and
-// other packages after refactoring the web handler registering.
+// TODO(a.garipov): Merge together with the implementations in [dhcpd] and other
+// packages after refactoring the web handler registering.
 type jsonError struct {
 	// Message is the error message, an opaque string.
 	Message string `json:"message"`
@@ -940,30 +948,40 @@ func cmdlineUpdate(opts options) {
 		return
 	}
 
-	log.Info("starting update")
+	// Initialize the DNS server to use the internal resolver which the updater
+	// needs to be able to resolve the update source hostname.
+	//
+	// TODO(e.burkov):  We could probably initialize the internal resolver
+	// separately.
+	err := initDNSServer(nil, nil, nil, nil, nil, nil, &tlsConfigSettings{})
+	fatalOnError(err)
 
-	if Context.firstRun {
-		log.Info("update not allowed on first run")
+	log.Info("cmdline update: performing update")
 
-		os.Exit(0)
-	}
-
-	_, err := Context.updater.VersionInfo(true)
+	updater := Context.updater
+	info, err := updater.VersionInfo(true)
 	if err != nil {
-		vcu := Context.updater.VersionCheckURL()
+		vcu := updater.VersionCheckURL()
 		log.Error("getting version info from %s: %s", vcu, err)
 
-		os.Exit(0)
+		os.Exit(1)
 	}
 
-	if Context.updater.NewVersion() == "" {
+	if info.NewVersion == version.Version() {
 		log.Info("no updates available")
 
 		os.Exit(0)
 	}
 
-	err = Context.updater.Update()
+	err = updater.Update(Context.firstRun)
 	fatalOnError(err)
 
+	err = restartService()
+	if err != nil {
+		log.Debug("restarting service: %s", err)
+		log.Info("AdGuard Home was not installed as a service. " +
+			"Please restart running instances of AdGuardHome manually.")
+	}
+
 	os.Exit(0)
 }
diff --git a/internal/home/i18n.go b/internal/home/i18n.go
index cc8da8fe..d9e3435c 100644
--- a/internal/home/i18n.go
+++ b/internal/home/i18n.go
@@ -54,6 +54,7 @@ type languageJSON struct {
 	Language string `json:"language"`
 }
 
+// TODO(d.kolyshev): Deprecated, remove it later.
 func handleI18nCurrentLanguage(w http.ResponseWriter, r *http.Request) {
 	log.Printf("home: language is %s", config.Language)
 
@@ -62,6 +63,7 @@ func handleI18nCurrentLanguage(w http.ResponseWriter, r *http.Request) {
 	})
 }
 
+// TODO(d.kolyshev): Deprecated, remove it later.
 func handleI18nChangeLanguage(w http.ResponseWriter, r *http.Request) {
 	if aghhttp.WriteTextPlainDeprecated(w, r) {
 		return
diff --git a/internal/home/options.go b/internal/home/options.go
index befc78a2..9d435b6e 100644
--- a/internal/home/options.go
+++ b/internal/home/options.go
@@ -229,7 +229,7 @@ var cmdLineOpts = []cmdLineOpt{{
 	updateNoValue:   func(o options) (options, error) { o.performUpdate = true; return o, nil },
 	effect:          nil,
 	serialize:       func(o options) (val string, ok bool) { return "", o.performUpdate },
-	description:     "Update application and exit.",
+	description:     "Update the current binary and restart the service in case it's installed.",
 	longName:        "update",
 	shortName:       "",
 }, {
diff --git a/internal/home/profilehttp.go b/internal/home/profilehttp.go
new file mode 100644
index 00000000..12e036c3
--- /dev/null
+++ b/internal/home/profilehttp.go
@@ -0,0 +1,102 @@
+package home
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/aghhttp"
+	"github.com/AdguardTeam/golibs/log"
+)
+
+// Theme is an enum of all allowed UI themes.
+type Theme string
+
+// Allowed [Theme] values.
+//
+// Keep in sync with client/src/helpers/constants.js.
+const (
+	ThemeAuto  Theme = "auto"
+	ThemeLight Theme = "light"
+	ThemeDark  Theme = "dark"
+)
+
+// UnmarshalText implements [encoding.TextUnmarshaler] interface for *Theme.
+func (t *Theme) UnmarshalText(b []byte) (err error) {
+	switch string(b) {
+	case "auto":
+		*t = ThemeAuto
+	case "dark":
+		*t = ThemeDark
+	case "light":
+		*t = ThemeLight
+	default:
+		return fmt.Errorf("invalid theme %q, supported: %q, %q, %q", b, ThemeAuto, ThemeDark, ThemeLight)
+	}
+
+	return nil
+}
+
+// profileJSON is an object for /control/profile and /control/profile/update
+// endpoints.
+type profileJSON struct {
+	Name     string `json:"name"`
+	Language string `json:"language"`
+	Theme    Theme  `json:"theme"`
+}
+
+// handleGetProfile is the handler for GET /control/profile endpoint.
+func handleGetProfile(w http.ResponseWriter, r *http.Request) {
+	u := Context.auth.getCurrentUser(r)
+
+	var resp profileJSON
+	func() {
+		config.RLock()
+		defer config.RUnlock()
+
+		resp = profileJSON{
+			Name:     u.Name,
+			Language: config.Language,
+			Theme:    config.Theme,
+		}
+	}()
+
+	_ = aghhttp.WriteJSONResponse(w, r, resp)
+}
+
+// handlePutProfile is the handler for PUT /control/profile/update endpoint.
+func handlePutProfile(w http.ResponseWriter, r *http.Request) {
+	if aghhttp.WriteTextPlainDeprecated(w, r) {
+		return
+	}
+
+	profileReq := &profileJSON{}
+	err := json.NewDecoder(r.Body).Decode(profileReq)
+	if err != nil {
+		aghhttp.Error(r, w, http.StatusBadRequest, "reading req: %s", err)
+
+		return
+	}
+
+	lang := profileReq.Language
+	if !allowedLanguages.Has(lang) {
+		aghhttp.Error(r, w, http.StatusBadRequest, "unknown language: %q", lang)
+
+		return
+	}
+
+	theme := profileReq.Theme
+
+	func() {
+		config.Lock()
+		defer config.Unlock()
+
+		config.Language = lang
+		config.Theme = theme
+		log.Printf("home: language is set to %s", lang)
+		log.Printf("home: theme is set to %s", theme)
+	}()
+
+	onConfigModified()
+	aghhttp.OK(w)
+}
diff --git a/internal/home/service.go b/internal/home/service.go
index 3aece1f2..c0fe845f 100644
--- a/internal/home/service.go
+++ b/internal/home/service.go
@@ -159,6 +159,38 @@ func sendSigReload() {
 	log.Debug("service: sent signal to pid %d", pid)
 }
 
+// restartService restarts the service.  It returns error if the service is not
+// running.
+func restartService() (err error) {
+	// Call chooseSystem explicitly to introduce OpenBSD support for service
+	// package.  It's a noop for other GOOS values.
+	chooseSystem()
+
+	pwd, err := os.Getwd()
+	if err != nil {
+		return fmt.Errorf("getting current directory: %w", err)
+	}
+
+	svcConfig := &service.Config{
+		Name:             serviceName,
+		DisplayName:      serviceDisplayName,
+		Description:      serviceDescription,
+		WorkingDirectory: pwd,
+	}
+	configureService(svcConfig)
+
+	var s service.Service
+	if s, err = service.New(&program{}, svcConfig); err != nil {
+		return fmt.Errorf("initializing service: %w", err)
+	}
+
+	if err = svcAction(s, "restart"); err != nil {
+		return fmt.Errorf("restarting service: %w", err)
+	}
+
+	return nil
+}
+
 // handleServiceControlAction one of the possible control actions:
 //
 //   - install:  Installs a service/daemon.
diff --git a/internal/home/service_linux.go b/internal/home/service_linux.go
index 39d572a0..e5dd2953 100644
--- a/internal/home/service_linux.go
+++ b/internal/home/service_linux.go
@@ -7,6 +7,8 @@ import (
 	"github.com/kardianos/service"
 )
 
+// chooseSystem checks the current system detected and substitutes it with local
+// implementation if needed.
 func chooseSystem() {
 	sys := service.ChosenSystem()
 	// By default, package service uses the SysV system if it cannot detect
diff --git a/internal/home/service_openbsd.go b/internal/home/service_openbsd.go
index 071775b9..4f94f0b4 100644
--- a/internal/home/service_openbsd.go
+++ b/internal/home/service_openbsd.go
@@ -30,6 +30,8 @@ import (
 // sysVersion is the version of local service.System interface implementation.
 const sysVersion = "openbsd-runcom"
 
+// chooseSystem checks the current system detected and substitutes it with local
+// implementation if needed.
 func chooseSystem() {
 	service.ChooseSystem(openbsdSystem{})
 }
diff --git a/internal/stats/stats.go b/internal/stats/stats.go
index 0ac8d9be..b1df74c1 100644
--- a/internal/stats/stats.go
+++ b/internal/stats/stats.go
@@ -180,7 +180,7 @@ func withRecovered(orig *error) {
 // type check
 var _ Interface = (*StatsCtx)(nil)
 
-// Start implements the Interface interface for *StatsCtx.
+// Start implements the [Interface] interface for *StatsCtx.
 func (s *StatsCtx) Start() {
 	s.initWeb()
 
diff --git a/internal/updater/check.go b/internal/updater/check.go
index 2bac6153..5de7ecfc 100644
--- a/internal/updater/check.go
+++ b/internal/updater/check.go
@@ -61,7 +61,7 @@ func (u *Updater) VersionInfo(forceRecheck bool) (vi VersionInfo, err error) {
 		return VersionInfo{}, fmt.Errorf("updater: HTTP GET %s: %w", vcu, err)
 	}
 
-	u.prevCheckTime = time.Now()
+	u.prevCheckTime = now
 	u.prevCheckResult, u.prevCheckError = u.parseVersionResponse(body)
 
 	return u.prevCheckResult, u.prevCheckError
@@ -92,7 +92,11 @@ func (u *Updater) parseVersionResponse(data []byte) (VersionInfo, error) {
 	info.AnnouncementURL = versionJSON["announcement_url"]
 
 	packageURL, ok := u.downloadURL(versionJSON)
-	info.CanAutoUpdate = aghalg.BoolToNullBool(ok && info.NewVersion != u.version)
+	if !ok {
+		return info, fmt.Errorf("version.json: packageURL not found")
+	}
+
+	info.CanAutoUpdate = aghalg.BoolToNullBool(info.NewVersion != u.version)
 
 	u.newVersion = info.NewVersion
 	u.packageURL = packageURL
diff --git a/internal/updater/updater.go b/internal/updater/updater.go
index 55c1d918..f042ab3c 100644
--- a/internal/updater/updater.go
+++ b/internal/updater/updater.go
@@ -104,49 +104,58 @@ func NewUpdater(conf *Config) *Updater {
 	}
 }
 
-// Update performs the auto-update.
-func (u *Updater) Update() (err error) {
+// Update performs the auto-update.  It returns an error if the update failed.
+// If firstRun is true, it assumes the configuration file doesn't exist.
+func (u *Updater) Update(firstRun bool) (err error) {
 	u.mu.Lock()
 	defer u.mu.Unlock()
 
 	log.Info("updater: updating")
-	defer func() { log.Info("updater: finished; errors: %v", err) }()
+	defer func() {
+		if err != nil {
+			log.Error("updater: failed: %v", err)
+		} else {
+			log.Info("updater: finished")
+		}
+	}()
 
 	execPath, err := os.Executable()
 	if err != nil {
-		return err
+		return fmt.Errorf("getting executable path: %w", err)
 	}
 
 	err = u.prepare(execPath)
 	if err != nil {
-		return err
+		return fmt.Errorf("preparing: %w", err)
 	}
 
 	defer u.clean()
 
-	err = u.downloadPackageFile(u.packageURL, u.packageName)
+	err = u.downloadPackageFile()
 	if err != nil {
-		return err
+		return fmt.Errorf("downloading package file: %w", err)
 	}
 
 	err = u.unpack()
 	if err != nil {
-		return err
+		return fmt.Errorf("unpacking: %w", err)
 	}
 
-	err = u.check()
-	if err != nil {
-		return err
+	if !firstRun {
+		err = u.check()
+		if err != nil {
+			return fmt.Errorf("checking config: %w", err)
+		}
 	}
 
-	err = u.backup()
+	err = u.backup(firstRun)
 	if err != nil {
-		return err
+		return fmt.Errorf("making backup: %w", err)
 	}
 
 	err = u.replace()
 	if err != nil {
-		return err
+		return fmt.Errorf("replacing: %w", err)
 	}
 
 	return nil
@@ -174,7 +183,7 @@ func (u *Updater) prepare(exePath string) (err error) {
 
 	_, pkgNameOnly := filepath.Split(u.packageURL)
 	if pkgNameOnly == "" {
-		return fmt.Errorf("invalid PackageURL")
+		return fmt.Errorf("invalid PackageURL: %q", u.packageURL)
 	}
 
 	u.packageName = filepath.Join(u.updateDir, pkgNameOnly)
@@ -204,6 +213,7 @@ func (u *Updater) prepare(exePath string) (err error) {
 	return nil
 }
 
+// unpack extracts the files from the downloaded archive.
 func (u *Updater) unpack() error {
 	var err error
 	_, pkgNameOnly := filepath.Split(u.packageURL)
@@ -228,38 +238,48 @@ func (u *Updater) unpack() error {
 	return nil
 }
 
+// check returns an error if the configuration file couldn't be used with the
+// version of AdGuard Home just downloaded.
 func (u *Updater) check() error {
 	log.Debug("updater: checking configuration")
+
 	err := copyFile(u.confName, filepath.Join(u.updateDir, "AdGuardHome.yaml"))
 	if err != nil {
 		return fmt.Errorf("copyFile() failed: %w", err)
 	}
+
 	cmd := exec.Command(u.updateExeName, "--check-config")
 	err = cmd.Run()
 	if err != nil || cmd.ProcessState.ExitCode() != 0 {
 		return fmt.Errorf("exec.Command(): %s %d", err, cmd.ProcessState.ExitCode())
 	}
+
 	return nil
 }
 
-func (u *Updater) backup() error {
+// backup makes a backup of the current configuration and supporting files.  It
+// ignores the configuration file if firstRun is true.
+func (u *Updater) backup(firstRun bool) (err error) {
 	log.Debug("updater: backing up current configuration")
 	_ = os.Mkdir(u.backupDir, 0o755)
-	err := copyFile(u.confName, filepath.Join(u.backupDir, "AdGuardHome.yaml"))
-	if err != nil {
-		return fmt.Errorf("copyFile() failed: %w", err)
+	if !firstRun {
+		err = copyFile(u.confName, filepath.Join(u.backupDir, "AdGuardHome.yaml"))
+		if err != nil {
+			return fmt.Errorf("copyFile() failed: %w", err)
+		}
 	}
 
 	wd := u.workDir
 	err = copySupportingFiles(u.unpackedFiles, wd, u.backupDir)
 	if err != nil {
-		return fmt.Errorf("copySupportingFiles(%s, %s) failed: %s",
-			wd, u.backupDir, err)
+		return fmt.Errorf("copySupportingFiles(%s, %s) failed: %s", wd, u.backupDir, err)
 	}
 
 	return nil
 }
 
+// replace moves the current executable with the updated one and also copies the
+// supporting files.
 func (u *Updater) replace() error {
 	err := copySupportingFiles(u.unpackedFiles, u.updateDir, u.workDir)
 	if err != nil {
@@ -287,6 +307,7 @@ func (u *Updater) replace() error {
 	return nil
 }
 
+// clean removes the temporary directory itself and all it's contents.
 func (u *Updater) clean() {
 	_ = os.RemoveAll(u.updateDir)
 }
@@ -297,9 +318,9 @@ func (u *Updater) clean() {
 const MaxPackageFileSize = 32 * 1024 * 1024
 
 // Download package file and save it to disk
-func (u *Updater) downloadPackageFile(url, filename string) (err error) {
+func (u *Updater) downloadPackageFile() (err error) {
 	var resp *http.Response
-	resp, err = u.client.Get(url)
+	resp, err = u.client.Get(u.packageURL)
 	if err != nil {
 		return fmt.Errorf("http request failed: %w", err)
 	}
@@ -321,7 +342,7 @@ func (u *Updater) downloadPackageFile(url, filename string) (err error) {
 	_ = os.Mkdir(u.updateDir, 0o755)
 
 	log.Debug("updater: saving package to file")
-	err = os.WriteFile(filename, body, 0o644)
+	err = os.WriteFile(u.packageName, body, 0o644)
 	if err != nil {
 		return fmt.Errorf("os.WriteFile() failed: %w", err)
 	}
diff --git a/internal/updater/updater_test.go b/internal/updater/updater_test.go
index dbf0e069..af9093cc 100644
--- a/internal/updater/updater_test.go
+++ b/internal/updater/updater_test.go
@@ -136,10 +136,10 @@ func TestUpdate(t *testing.T) {
 	u.packageURL = fakeURL.String()
 
 	require.NoError(t, u.prepare(exePath))
-	require.NoError(t, u.downloadPackageFile(u.packageURL, u.packageName))
+	require.NoError(t, u.downloadPackageFile())
 	require.NoError(t, u.unpack())
 	// require.NoError(t, u.check())
-	require.NoError(t, u.backup())
+	require.NoError(t, u.backup(false))
 	require.NoError(t, u.replace())
 
 	u.clean()
@@ -215,10 +215,10 @@ func TestUpdateWindows(t *testing.T) {
 	u.packageURL = fakeURL.String()
 
 	require.NoError(t, u.prepare(exePath))
-	require.NoError(t, u.downloadPackageFile(u.packageURL, u.packageName))
+	require.NoError(t, u.downloadPackageFile())
 	require.NoError(t, u.unpack())
 	// assert.Nil(t, u.check())
-	require.NoError(t, u.backup())
+	require.NoError(t, u.backup(false))
 	require.NoError(t, u.replace())
 
 	u.clean()
diff --git a/openapi/CHANGELOG.md b/openapi/CHANGELOG.md
index cc30989d..b583ad60 100644
--- a/openapi/CHANGELOG.md
+++ b/openapi/CHANGELOG.md
@@ -6,6 +6,33 @@
 
 
 
+## v0.107.22: API changes
+
+### `POST /control/i18n/change_language` is deprecated
+
+Use `PUT /control/profile/update`.
+
+### `GET /control/i18n/current_language` is deprecated
+
+Use `GET /control/profile`.
+
+* The `/control/profile` HTTP API has been changed.
+
+* The new `PUT /control/profile/update` HTTP API allows user info updates.
+
+These `control/profile/update` and `control/profile` APIs accept and return a
+JSON object with the following format:
+
+```json
+{
+  "name":"user name", 
+  "language": "en",
+  "theme": "auto"
+}
+```
+
+
+
 ## v0.107.20: API Changes
 
 ### `POST /control/cache_clear`
diff --git a/openapi/openapi.yaml b/openapi/openapi.yaml
index b3135477..68401830 100644
--- a/openapi/openapi.yaml
+++ b/openapi/openapi.yaml
@@ -962,6 +962,9 @@
           'description': 'OK.'
   '/i18n/change_language':
     'post':
+      'deprecated': true
+      'description': >
+        Deprecated: Use `PUT /control/profile` instead.
       'tags':
       - 'i18n'
       'operationId': 'changeLanguage'
@@ -980,6 +983,9 @@
           'description': 'OK.'
   '/i18n/current_language':
     'get':
+      'deprecated': true
+      'description': >
+        Deprecated: Use `GET /control/profile` instead.
       'tags':
       - 'i18n'
       'operationId': 'currentLanguage'
@@ -1145,6 +1151,20 @@
       'responses':
         '302':
           'description': 'OK.'
+  '/profile/update':
+    'put':
+      'tags':
+        - 'global'
+      'operationId': 'updateProfile'
+      'summary': 'Updates current user info'
+      'requestBody':
+        'content':
+          'application/json':
+            'schema':
+              '$ref': '#/components/schemas/ProfileInfo'
+      'responses':
+        '200':
+          'description': 'OK'
   '/profile':
     'get':
       'tags':
@@ -2335,6 +2355,19 @@
       'properties':
         'name':
           'type': 'string'
+        'language':
+          'type': 'string'
+        'theme':
+          'type': 'string'
+          'description': 'Interface theme'
+          'enum':
+            - 'auto'
+            - 'dark'
+            - 'light'
+      'required':
+        - 'name'
+        - 'language'
+        - 'theme'
     'Client':
       'type': 'object'
       'description': 'Client information.'
diff --git a/scripts/make/build-docker.sh b/scripts/make/build-docker.sh
index 917e7771..38b1ea30 100644
--- a/scripts/make/build-docker.sh
+++ b/scripts/make/build-docker.sh
@@ -85,7 +85,7 @@ in
 esac
 readonly docker_image_full_name docker_tags
 
-# Copy the binaries into a new directory under new names, so that it's eaiser to
+# Copy the binaries into a new directory under new names, so that it's easier to
 # COPY them later.  DO NOT remove the trailing underscores.  See file
 # scripts/make/Dockerfile.
 dist_docker="${dist_dir}/docker"
diff --git a/scripts/make/build-release.sh b/scripts/make/build-release.sh
index 1c8cb9c0..72ba8aeb 100644
--- a/scripts/make/build-release.sh
+++ b/scripts/make/build-release.sh
@@ -7,22 +7,18 @@
 # Experienced readers may find it overly verbose.
 
 # The default verbosity level is 0.  Show log messages if the caller requested
-# verbosity level greater than 0.  Show every command that is run if the
-# verbosity level is greater than 1.  Show the environment if the verbosity
-# level is greater than 2.  Otherwise, print nothing.
+# verbosity level greater than 0.  Show the environment and every command that
+# is run if the verbosity level is greater than 1.  Otherwise, print nothing.
 #
 # The level of verbosity for the build script is the same minus one level.  See
 # below in build().
 verbose="${VERBOSE:-0}"
 readonly verbose
 
-if [ "$verbose" -gt '2' ]
+if [ "$verbose" -gt '1' ]
 then
 	env
 	set -x
-elif [ "$verbose" -gt '1' ]
-then
-	set -x
 fi
 
 # By default, sign the packages, but allow users to skip that step.
@@ -188,9 +184,6 @@ build() {
 	#
 	# Set GOARM and GOMIPS to an empty string if $build_arm and $build_mips are
 	# the zero value by removing the hyphen as if it's a prefix.
-	#
-	# Don't use quotes with $build_par because we want an empty space if
-	# parallelism wasn't set.
 	env\
 		GOARCH="$build_arch"\
 		GOARM="${build_arm#-}"\