What it does
KMail is a KDE email client with inline OpenPGP, PGP/MIME and S/MIME support. It integrates contact encryption preferences, calendar invitations, filtering and offline mail access.
KMail connects encrypted correspondence with the rest of the KDE personal-information tools. It can load contacts and their cryptographic preferences from KAddressBook, while invitations can be added to KOrganizer. That reduces the need to treat each message as a disconnected encryption task.
The application page lists inline OpenPGP, PGP/MIME and S/MIME, alongside standard mail protocols. Release notes also describe showing recipient-key validity and expiration warnings in the composer. It is a client for existing accounts, so the provider and the recipient’s available keys remain part of the setup.
Strengths
- OpenPGP and S/MIME formats are documented.
- Contact encryption preferences integrate with KAddressBook.
- The composer displays recipient-key validity information.
Best for
- KDE users who want encrypted mail integrated with contacts and scheduling
Sources
- KMail - KDE Applications (Oct 26, 2026)