Release Notes — Thunderbird

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.
System Requirements: Details
Non-ASCII IMAP tags could exceed server length limits and be rejected
Zoom Text Only option did not work in the View menu
Multiple messages were printed even after canceling the print dialog
Save All and Detach All failed for attachments with invalid filename paths
First Wrap Long Lines toggle did nothing in View Source
POP3 NTLM authentication failed because the password was sent incorrectly
Search Messages menu option was enabled but did not work for saved search folders
Quick Find shortcut (/) only worked after Ctrl+F was used once
Unicode email addresses could hide different Reply-To destinations
Newsgroups with UTF-8 names could display duplicate or incorrect messages
View > Folders did nothing in Calendar and Tasks tabs
Global search results did not display recipients in the To field
Forwarding malformed MIME messages could omit attachments
Retry and Save Locally failed after a sent-folder copy error
Closing an unmodified compose window prompted to save when using Body Text
MP4 attachments could be truncated when forwarding messages
Inline images disappeared when editing local or POP messages as new
EWS/Graph accounts could fail when outgoing server settings were incomplete
Account Hub Edit Configuration did nothing for Exchange and Graph accounts
First message filter condition could not be removed even when others existed
CardDAV address book sync stopped when the server rejected an invalid sync token
CardDAV passwords were not saved, causing repeated login prompts after restart
Thunderbird could hang on startup when restoring IMAP message and PDF tabs
Malformed message database files could cause excessive CPU usage
IMAP namespace root folders were inaccessible due to duplicated folder names
Excessive Microsoft Graph requests caused throttling and delayed message display
SMTP addresses with line breaks could inject unintended commands
POP3 sessions remained active after canceling the password prompt
Remote content could load in news articles with missing message headers
RSS feeds could inject arbitrary Message-ID and References headers
Large ICS calendar files could exhaust memory and freeze Thunderbird
CalDAV calendars could stop syncing after a network error until restart
Account Hub failed to discover CalDAV calendars for OAuth2 accounts
Yearly recurring events with multiple times per day only appeared at the first time
Visual and UX improvements
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