Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> I'm trying to install packages from elpa. However...
>>
>> Failed to verify signature archive-contents.sig:
>> Bad signature from 066DAFCB81E42C40 GNU ELPA Signing Agent (2019) <
>> elpasign@elpa.gnu.org>
>> Command output:
>> gpg: Signature made dom 31 mar 2024 11:30:08 CEST
>> gpg:                using RSA key C433554766D3DDC64221BFAA066DAFCB81E42C40
>> gpg: BAD signature from "GNU ELPA Signing Agent (2019) <
>> elpasign@elpa.gnu.org>" [unknown]
>
> I don't know why you get a "BAD signature message":  The 2019 key is
> expired so AFAIK we don't use it any more.  You need to install the
> `gnu-epa-keyring-update` package (or use a more recent version of Emacs).

No further comments here, so I'm boldly assuming that the above fixed
it.

I'm therefore closing this bug report.