diff --git a/lib/esp-knx-ip-0.5.1/DPT.h b/lib/esp-knx-ip-0.5.1/DPT.h
index 71045b103..3529d51af 100644
--- a/lib/esp-knx-ip-0.5.1/DPT.h
+++ b/lib/esp-knx-ip-0.5.1/DPT.h
@@ -40,13 +40,14 @@ typedef enum __dpt_3_007
 
 typedef enum __weekday
 {
+	DPT_10_001_WEEKDAY_NODAY = 0,
 	DPT_10_001_WEEKDAY_MONDAY = 1,
 	DPT_10_001_WEEKDAY_TUESDAY = 2,
 	DPT_10_001_WEEKDAY_WEDNESDAY = 3,
 	DPT_10_001_WEEKDAY_THURSDAY = 4,
 	DPT_10_001_WEEKDAY_FRIDAY = 5,
 	DPT_10_001_WEEKDAY_SATURDAY = 6,
-	DPT_10_001_WEEKDAY_SUNDAY = 8,
+	DPT_10_001_WEEKDAY_SUNDAY = 7,
 } weekday_t;
 
 typedef struct __time_of_day