Due to the Chrysalis network update on Mainnet that happened April 28, 2020, many old questions/answers (particularly those around trinary encoding and Winternitz signatures, but also low-level questions about message format internals) became obsolete and only of historic interest.
How should we go treat them?
I noticed that Antonio Nardella started posting answers to those questions. I myself am tagging all those questions with the legacy-protocol tag when I stumble upon them.
But I believe we could need more coordination here. And maybe some tooling (if it exists) like a displayed banner to make it more obvious to newbies that those questions are not relevant to the IOTA network deployed today and only of historic interest.
EDIT As pointed out in the answer below, we could create a custom post notice for that. Any suggestions for the wording are appreciated :)