New in the 1.9.x rtl (not yet in the docs)

The following stuff is new in 1.9.x and is not yet in the docs:

• A lot of integer types are changed to SizeInt/SizeUInt to have common declarations for 32 and 64 Bit targets.

The following routines are new in the 1.9.x rtl and aren't yet documented:

 function UnicodeToUtf8(Dest: PChar; Source: PWideChar; MaxBytes: SizeInt): SizeInt;
 function UnicodeToUtf8(Dest: PChar; MaxDestBytes: SizeUInt; Source: PWideChar; SourceChars: SizeUInt): SizeUInt;
 function Utf8ToUnicode(Dest: PWideChar; Source: PChar; MaxChars: SizeInt): SizeInt;
 function Utf8ToUnicode(Dest: PWideChar; MaxDestChars: SizeUInt; Source: PChar; SourceBytes: SizeUInt): SizeUInt;

See also Language related articles for compiler stuff not yet documented.

UPD: Now it documented in UTF-8 page.