Hi Martin,
I perhaps did not express that clearly. 2.19.80 is in the development line and it is technically marked 'unstable' as opposed to the 2.18.2 stable release, because anything not 2.18.2 is called 'unstable'. But this does not mean it is unstable and unusable. In actual use and practice the later 2.19 releases hardly ever crash and show very few defects. That's what I mean by stable. I use the 2.19 series for difficult new Complexity school scores and everything is good, no problems. Not a single crash even with long scores in a couple of years.