You can integrate your Mailfence account into Thunderbird using SMTP and IMAP/POP. This feature is available with Entry, Pro, and Ultra subscription plans.
1. Open your Thunderbird client (version 152.* or later) and go to File > New.

2. Click on Existing Mail Account.

3. Enter your Mailfence account Display name and Email address. Click on Continue.

4. Choose a protocol (IMAP or POP). Click on Continue.

5. Enter your Mailfence account password. Click on Continue.

6. You can also optionally configure your Mailfence account’s Contacts and Calendar. To do so, click Continue. Otherwise, click Skip.

6. Click on Finish.

You can also sync Mailfence Contacts and Calendar events with CardDAV and CalDAV or using Exchange ActiveSync. Mailfence Group member chat function can also be configured using XMPP.