I haven't run a burner mission in a few weeks, and not since the missile modules and associated changes went live. I haven't messed with anything on SISI either.
I went trolling around forums this morning looking for potential impact to my burner fits (many of which are rockets or LML) but saw no particular warnings about old fits not working anymore.
If you've got experience (positive or negative) with burner fits and the most recent release, please drop me a note ingame or leave a comment. Thanks!