SUMMARY
We have upgraded approximately 80 clients with GPG4win from version 4.3.1 to 4.4.0, and the Outlook add-in doesn’t work anymore because the new version 4.4.0 uses an unsigned "gpgol.dll" for the Outlook add-in. In version 4.3.1, the "gpgol.dll" is still signed. This issue impacts us because we need to configure our Office 365 according to the BSI (GER: „Bundesamt für Sicherheit in der IT“, EN: „Federal Office for IT Security”) standards for Office products. The Federal Office for IT Security regulations state that no unsigned add-ins or macros can be executed. 

STEPS TO REPRODUCE
Addin File:
1. "C:\Program Files\Gpg4win\bin\gpgol.dll"
2. "Properties" > "Digitial Signatures" tab is missing.

Outlook Setup:
1. Open "Option" > "Trust Center"  > "Trust Center Settings" > "Macro Settings"
2. Check Option "Notification for digitally signed macros, all other macros disabled
3. Check Option "Apply macro security setting to installed add-ins"

Alternative Approach (Registry Editor) -> we use GPO's
HKEY_CURRENT_USER\Software\Policies\Microsoft\office\16.0\outlook\security
(DWORD) LEVEL = 3
(DWORD) donttrustinstalledfiles = 1

SOFTWARE/OS VERSIONS
Windows: Wondows 11 Version 2009(x86_64)
Software: GPG4Win 4.4.0