I see that QT5 version is back.

However, 2.1.3 QT5 does not work on Windows 7. It seems you compiled it without targeting that OS as a minimum, so it tries to use KERNEL32.dll calls introduced in Windows 8 such as CreateFile2 instead of CreateFileW. It leads to the fatal error.

If I replace that call in libarchive.dll, then GPGFrontend launches.

$ sfk.exe replace -pat /CreateFile2/CreateFileW/ -dir . -file *.* -yes
[total hits/matching patterns/non-matching patterns]
[003/1/0] libarchive.dll
109 files checked, 1 changed.