diff --git a/Differences.md b/Differences.md
index dc0fb22..32af9c5 100644
--- a/Differences.md
+++ b/Differences.md
@@ -36,5 +36,6 @@ Known issues are essentially bugs, misfeatures, and omissions considered such, a
 1. ``collections.deque`` class is not implemented.
 1. ``memoryview`` object not implemented.
 1. Container slice assignment/deletion is only partially implemented. [#509](https://github.com/micropython/micropython/issues/509)
+1. 3-argument slicing is only partially implemented.
 1. <strike>Keyword and keyword-only arguments need more work</strike> [#466](https://github.com/micropython/micropython/issues/466), [#524](//github.com/micropython/micropython/issues/524).
 1. Only basic support for ``__new__`` method is available [#606](//github.com/micropython/micropython/issues/606), [#622](//github.com/micropython/micropython/issues/622).
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