What's new • Enterprise policies now support Thunderbird-specific preferences Fixes • Microsoft hosted email users may have re-authenticate with OAuth2; Admin approval may be required depending on local policies. • Localized builds and langpacks now use "comm-l10n" repository; downstream builds using official langpacks should not need to make changes • Having too many folders open at startup caused loss of MSF files • Copying an email from one local folder to another local folder sometimes caused "Another Operation is using the folder" error on Windows 7 • Email address pill allowed for incorrectly formatted email addresses • Creating security exceptions for messages sent using a self-signed certificate failed if hostname contained uppercase letters • S/MIME certificate verification was prohibitively slow • OpenPGP key import failed for key blocks with comments that contain Unicode characters • Chat conversation sidebar was too wide under certain circumstances, making scrollbar unusable • On Mac, deleting events from Today Pane with "Backspace" key deleted selected messages instead • Various security fixes Known issues • OAuth2 authentication not working for Microsoft 365 Enterprise accounts