Expirion 5.12 is based on Devuan 5 it does not use systemd but instead uses RunIt. They are now in the folder called Expirion 5 Old
Expirion 6.4 is based on Devuan 6 and it does not have systemd but uses SysVInit
All ISOs are 64Bit only (x64) and only boot on x64 machines
So what sets this apart from Devuan, not much really the Kernel for newer hardware support and LibreOffice has been updated, and some minor software & firmware changes, but that is about it and added some...