Source: sogo Version: 5.4.0-1
The README.Debian file of the SOGo package states there is no S/MIME support in the webinterface due to the package being built using GnuTLS instead of openssl while a switch to openssl has been done in commit f2d148cd
OpenPGP_0xD61E22D000471E9B.asc
Description: OpenPGP public key
OpenPGP_signature
Description: OpenPGP digital signature