> I decided to create a custom channel that includes the latest version
> of gnupg and its dependent libraries. To do this I used the gnupg.scm
> file from Guix as a template but modified the versions and hashes of
> the relevant package definitions. I then used my gnupg.scm file and
> did a test build and was able to successfully build the latest version
> of gnupg, and its libraries.

Have you renamed the module defined in your copy of gnupg.scm? If it is
still (gnu packages gnupg) it will probably be shadowed by the module in
base guix.

> I then created a signed git repo with the custom channel and included
> it in my ~/.config/guix/channels.scm. A guix pull recognizes my
> channel and apparently everything is signed as it should be since it
> seems to be pulled in without errors. However, when I then run
>
> guix show gnupg
> or
> guix package --list-available | grep gnupg

Have you checked that the guix command you are using is not the system
default (/run/current-system/profile/bin/guix)? Normally it isn't, but
it could have kept it if you were using it before the pull. If this is
the case, it should get fixed just by logging out and back in.

If these don't help you could try running

guix shell -e '(@ (your channel gnupg module) gnupg-variable-name)'

replacing the module and variable name with correct values. This should
either bring the updated gnupg package into a temporary shell session or
give an error that we can use to debug further.

- Saku