Due to T6203, the IMAP-Fix is still not integrated in the 3.1.25-codebase, used by "GnuPG VS Desktop".
The actual version of "GnuPG VS Desktop" / "Gpg4Win" 3.1.25 uses GpgOL 2.5.4 and is still based on 3.1.xx-codebase:
https://gnupg.com/vsd/version-3.1.25.de.html (Versionen der Komponenten)
https://gnupg.com/vsd/version-3.1.25.html (Versions of the Components)
When the patch from T6203 is not applied, encrypted communication with IMAP-Mailboxes is not possible.
Best Regards,
Veit Berwig