UnrealIRCd 5 is also affected by the critical bug. Other issues go all the way back to 3.2.x. Please understand that running End Of Life versions is a REALLY BAD idea.
Read the end of https://forums.unrealircd.org/viewtopic.php?t=9487 "Note to UnrealIRCd 5 and other EOL versions" and "Final words: the danger of AI is real". #IRC