Beta Notes

Thunderbird Desktop

Version 136.0beta | Released February 6, 2025

Check out the notes below for this version of Thunderbird. As always, you’re encouraged to tell us what you think, ask for help, or file a bug in Bugzilla.

These notes apply to Thunderbird version 136 beta 2 released February 13, 2025.

System Requirements: Details

  • Windows: Windows 10 or later
  • Mac: macOS 10.15 or later
  • Linux: GTK+ 3.14 or higher

What’s New

new

Messages are automatically adapted to dark mode with a quick toggle in the header.

new

New "Appearance" Settings UI to globally control message threading/sorting order.

What’s Changed

changed

Criteria for closing idle message databases.

What’s Fixed

fixed

Thunderbird Release channel was not displayed in "About Thunderbird".

fixed

Crash could occur when shutting down during MAPI send.

fixed

The error message for compacting a corrupted local folder was not useful.

fixed

Deleting or detaching attachments in a saved .eml file appeared to work but failed.

fixed

Some messages may have been threaded incorrectly in unified folders.

fixed

Unified folders could become unusable instead of being automatically rebuilt.

fixed

Folders at level 3+ were not auto-discovered when IMAP subscriptions were ignored.

fixed

New subfolder did not inherit parent view, sort order, sort type, or columns.

fixed

With "Fetch headers only" enabled, messages could not be sorted by size.

fixed

Selecting starred messages did not update immediately.

fixed

Marking a unified folder as favorite did not show it in favorite folders.

fixed

The UI could falsely report a message as encrypted when a null cipher was used.

fixed

Search messages dialog list could not be sorted by clicking the header icon.

fixed

Sending to multiple SMTPs could fail silently due to missing address book.

fixed

Changing the UI font size did not apply to some dialogs.

fixed

Deleted Gmail messages stayed visible until compact/expunge, despite settings.

fixed

Add-ons: Context menu entries were incorrectly aligned.

fixed

Some functionality was missing for newsgroup messages opened from a file or URI.

fixed

Visual and UX improvements

Fixed in beta 2

What’s Fixed

fixed

Middle-click autoscroll cursor appeared without arrows instead of expected design.

fixed

Release channel incorrectly showed What's New page after update.

fixed

Notifications for new mail were not showing for IMAP.

fixed

Message and folder lists could display incorrect line spacing after restart.

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