eM Client

Link

https://www.emclient.com/

• Commercial email client for [Windows](…/Microsoft Windows/), macOS, Android and iOS
• Supports mails, calendars, tasks, notes
• Supports [Microsoft 365](…/Microsoft 365/) shared mailboxes and groups (using EWS)
• Supports PGP encryption (using internal implementation based on “Bouncy Castle”)

Resources

• How to use Quick Actions

Improvement suggestions

• Support locally installed GnuPG/OpenKeyChain to avoid having to maintain keys in several places
• Do not block the main window during copy/move operations

FAQ

Show colleague’s calendars (EWS)

You might want to check View multiple calendars in one Exchange account - Calendar - eM Client, however that did not work for me 😟