On 1/9/2020 5:20 PM, between "Wilfred van Velzen : August Abolins":

 AA>> Further to your preceding message, you sent it signed with
 AA>> SHA1.

 WvV> Yeah, I already thought so. It's the default in my older
 WvV> gpg version. Let me try and change that...

TB 2.0.0.24 warned me with this:

gpg command line and output:
C:\Program Files\gnupg\bin\gpg.exe
gpg: Signature made 01/09/20 17:20:12 Eastern Standard Time
gpg:                using RSA key 3BB37DA84A97932B
gpg: BAD signature from "Wilfred van Velzen " [unknown]

It is warning me that you are not the person who claims to have written
that?

Maybe the new and old gpg programs are using different local key files
on your pc?

  ../|ug

--- Thunderbird 2.0.0.24 (Windows/20100228)