WinRAR 7.xx cannot create RAR4 archives anymore. Keep a copy of 6.24 around if you depend on it. Only creation (and updating) is affected, listing and extracting still works.
Nothing wrong with RAR5 itself, it's just that sometimes I need to send files to non-tech savvy people and they often have outdated software and whatever program they use tells them that the archive is corrupt..
There are no more 32-bit versions it seems. I hope someday the ARM64 build And a Mac version for WinRAR (tentatively named MacRAR)