Your debug log was created by a v5 Pi-hole.
If that's still operational, you should at least take a backup if you haven't followed our recommendations from Introducing Pi-hole v6 and done so before, and maybe you should also stick with it.
Pi-hole does not support PogoPlugs with precompiled binaries for some time now, but you may be able to compile it yourself, see Building Pi-hole v6.0 on Pogoplug V2.