Going back a version shouldn't give any problems with the desk however you do, obviously, lose any new features and there is, potentially, a risk that your show files do not load. In practice, if you haven't used any of the new features, these probably won't bother you,
7.14.4 was the final release for the legacy desks (Frog2, LeapFrog, Solution, Orb) - You don't want this version.
You want 7.14.3 for FLX & FLX S and the main difference is that you will go back to a maximum of 48 fixtures and fewer playbacks. Make sure you backup you v8 showfile. If you have used fixture numbers or playback numbers greater than the v7 limits then edit your show file to fit v7 and back that up to load after installing v7
The beta test forum for the new version (currently known as v8.0.0 build 11) seems to have been greeted with general apathy, possibly explained by being released when pantomimes are prevalent. There are no new new features and it consists of bug fixes for live version (v8.0.0 build 8). I don't know why other testers have failed to respond - for myself, I'm a full FLX and LeapFrog user and I'm not very interested in the newer versions now that FLX S has become the focus - I prefer to stick with v7 for now but might make a move to Chamsys.
There has only been one tester response. This may have been on an FLX S and was favourable but did not cover any programming functions.I suspect FLX S users are under represented among beta testers.