bug#37025: [found the culprit]

[Glenn Morris]

Teemu Likonen wrote:

> Thanks for the report and bisecting. I think we can fix the bug by
> including "--sender" option only with openpgp protocol (i.e. gpg).

gpg --sender
   -> gpg: invalid option "--sender"  # RHEL 7.6 with gpg 2.0.22

The option seems to only by present since gpg 2.1.15.
https://gnupg.org/download/release_notes.html

Ideally you should test if it is supported or not.