The main issue was that people were trying to leave the mini hacks on the SD card and doing the forced firmware update causing it to fail, but even once they realized to remove that they found that obviously the mini hacks doesn’t work anymore, at least not for RTSP and was causing other symptoms too.
Not sure about the “official” RTSP firmware but one has to assume if they are forcing out some new authentication mechanism or encryption key, etc it would affect all older firmwares.