QT5 has some new bugs, yes.
But it also fixed some other issues that was holding other things back.
M$ ending XP support just
helped 
dropping 'maintain compatibility' self imposed restraint
Sigil7.x will not run on my old AMD Athelon (no SSE2), so now I just use it for archiving as it still connects to my network.
I consider myself lucky that I have not hit walls before this.