The matter on what is officially supported is a disconnected communication happening from a few different sources. Just because we have x64 links out there doesn't mean that is what we vet from a stability perspective. All of our Windows builds that we CI and get pushed out in the installer are x86
Anytime I've seen x64 compilations on Windows there's been all kinds of weird anomalies. On Linux, we use a mix and we at least have largest servers in the community able to vet and QA the code as we are forced to deal with the issues that come up but there really aren't any in today's world after the many many years of work gone into the core
If you want to have a stable experience, follow what the installer instructions set out for versions and you'll be golden.
By all means if you want to spearhead x64 and troubleshoot weird issues just like the one in this thread, be my guest, because it will simply lead to time sinks. x64 definitely compiles and you can run a server on it and things can appear fine, but segmentation faults can send you down an infinite rabbit hole. If you want a stable environment, I would definitely recommend following what's here:
https://github.com/EQEmu/Server/wiki...-the-installer
Later versions of Perl, you don't know how Perl XS is going to behave, what reserved words are now no longer reserved and then produce a stack trace when the function is invoked in a zone. There's been a lot of radical changes further down the Perl line as well and we see no real reason to even consider support for later versions because the C interface has been absolutely terrible hence the drive to have support for languages such as LUA which are far more elegant and mature for said use case
Hopefully that helps a bit