[DiapDealer]

Sigil 2.6.2 is fine. It's still using Qt6.8.2. That version ran fine on the same machine I was testing on too. It wasn't until I installed a beta build of Sigil with Qt6.9.2 that my version of the runtime was insufficient.

I will say that it was a CI-built version of Sigil, so it's entirely possible it was the version of Visual Studio used to compile Sigil that caused the problem. But the fact of the matter is: the version of Visual Studio installed on github's action runner images is eventually going to be the version I use to make Sigil release builds on my local machine. So it's still only a matter of time before it becomes a factor.