I am planning to make an unstable 5.0.3 release of Lexilla, Scintilla, and SciTE in a few days.
There are some quite significant changes to Scintilla in the ways various elements are displayed and the APIs used to control these. Selection, caret, hot spot, and visible whitespace drawing has changed.
Type-safe headers are available for accessing the Scintilla API from C++ client code.
There could be some more bug fix 5.0.x releases but features planned for 5.x have now been committed and its less likely that there will be substantive changes before 5.1.0 and stability is declared. This should not discourage anyone from objecting to the changes since 4.x - its better to fix any problems now.
The biggest change to Lexilla is that a Julia lexer has been added.
SciTE has changed little apart from changes that originated in Lexilla and Scintilla.