Offline for a few years... update needed!

[Quarnero]

@rootapoottoot

When I ran apt list pureos-archive-keyring , it said
Listing... Done pureos-archive-keyring/now 2016.09 all [installed,local]

Yes, you need replacement for sure (sorry for not making this clear, the one from 2016 is just some obsolete key, not useful any more):

@Quarnero

sudo dpkg --install pureos-archive-keyring_2021.11.0_all.deb