René J.V. Bertin posted on Fri, 22 Sep 2017 12:04:47 +0200 as excerpted: > On Friday September 22 2017 12:59:12 Nikos Chantziaras wrote: > >>So instead I upgraded to Qt 5.9.1, which I was extremely reluctant to >>do; on Gentoo, the Qt 5.9 packages are marked with: >> >> "Guaranteed to break your system horribly or your money back." > > Oh, that. Probably because 5.9 is a Qt LTS release? ;) Gentoo user here too, not on qt 5.9 yet, but following live-git kde and the gentoo/kde overlay, so I have some information from that... The problem is that qt-5.8 had some major API changes... and rather serious actual breakage as well (I've seen some of the comments from kde devs as they stumbled on the breakage and had to figure out whether to work around it or leave whatever functionality broken and just tell folks qt 5.8 was broken and that 5.9 should be fixed). 5.9 is supposed to have fixed the worst actual breakage from 5.8, but the API changes remain. I've not upgraded to it here yet, but the warning is because various qt-based apps are likely not yet upgraded to work with the new 5.9 API, and will fail to build or once built, will crash or have missing functionality, until they adjust to the new API. Chances are, however, that if you run live-git or current release kde, and don't have other non-kde qt5 based apps on your system that are lagging, most of the qt 5.9 upgrade problems are hopefully fixed by now, and since 5.7 was bugged for you, any problems you do see will be equal to or less than the ones you'd have by sticking to 5.7. But if you haven't done a full rebuild of all qt-5 based apps since upgrading to 5.9, be aware that you may still encounter some breakage when rebuilding and/or at runtime, thus that gentoo warning, until they've fixed the known breakages, including those that won't affect most people as they're in obscure packages. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman