I have Bitcoin Core 0.21.0 right now and it's complaining about "Warning: unknown rules activated (versionbit 2)". Probably something to do with taproot. So before I upgrade Bitcoin Core, just wanted to make sure Armory is compatible.
Disregard the warning. It simply means the node cannot understand the bits that signal Taproot. It doesn't affect your ability to make transactions or discover peers in any way.