[branch gsoc-2022-chariri-2, commit 8d73df1] Hi Werner,
I've pushed a commit supporting older Qt versions (5.12). But I still recommend upgrading Qt since honestly, I don't know if I'll accidentally use more new features. On the other hand, Qt 5 has ceased to release new "minor" versions, so 5.15 would be the last, and I currently don't plan to go to Qt 6.
Cheers, Charlie Jiang
