11.19 came out June 10 and the post mentioning future versions was June 29, so the post definitely didn't mean 11.19 would contain the fix.
I believe current Opus 12 betas have the proposed fix, if you want to give them a try.
12.0.8 from July 1 included this change in the release notes:
When setting EXIF tags in pictures, Opus will no longer use UTF-8 for fields that never require it (e.g. "Date Taken"). This is to prevent compatibility problems with software that has trouble with the UTF-8 BOM header in certain fields (e.g. Explorer).