ScriptBasic core hasn't changed since 2005.
For some while my updates have principally been adding to or improving the IDE, libraries, tools and example programs rather than the 'core'. It's one of the big differences between
BBC BASIC for Windows and
BBC BASIC for SDL 2.0 of course; in the former the IDE was written in C because at the time (18+ years ago) interpreted BASIC wasn't fast enough for that task. Now, only the core interpreter needs to be written in assembler code and/or C, everything else (IDE, libraries, tools, utilities) can themselves be written in BASIC, because the performance is acceptable.
One valuable side-effect of all these add-ons being themselves coded in BASIC is that they are automatically CPU and OS-agnostic and will run on all the supported platforms without a build environment (C compiler, linker or whatever) - or the expertise to use it - needing to be available.