With some discussion of Scintilla 5.0 on `scintilla-interest` mailing list, I'm wondering if it might be worthwhile to just hold off until it's released, and then jump straight from 3 to 5. If/when I do this, I'm probably going to dedicate a day or two on a weekend to port it. I'd be pretty annoyed if after all the effort we were still a major version out of date and someone has to deep dive into the porting efforts all over.