Thunderbird 38.0.1

What's new in this version:

NEW:
- GMail supports OAuth2 authentication, removing the need to manually select "allow less secure applications" in Google options for the account. (bug 849540)
- Ship Lightning calendar addon with Thunderbird and enable with an opt-out dialog (bug 1113183)
- Filter sent messages (bug 11039)
- Filter messages when archived (bug 479823)
- Enable search in multiple/all address books (bug 170270)
- Add support for Yahoo Messenger in Chat (bug 955574)
- Support Internationalized domain name URLs for RSS feeds (Bug 1018589)
- Show expanded columns in folder pane (bug 464973)
- Allow file-per-message (maildir) local message storage (bug 845952)
- Add a Learn more link to the support page in feeds subscribe dialog (bug 1053782)
- Add reading position marker line to conversations (bug 760762)
- The editor for twitter should show inputtable character count (bug 736002)

CHANGED:
- Thunderbird will no longer use SHA-1 to sign messages (bug 1018259)
- Removed rarely used character sets: T.61-8bit, non-encoding Mac encoders, VISCII, x-viet-tcvn5712, x-viet-vps x-johab, ARMSCII8 , map us-ascii to windows-1252, ISO-8859-6-I and -E and ISO-8859-8-E, (bug 1068505 and others.)
- Disable CONDSTORE support for IMAP to prevent discrepancies in IMAP message status (deleted, unread) on some servers (bug 912216)
- Make OpenSearch queries open in the user's default browser (bug 1120777)
- Default to using SSL for XMPP and IRC. This might cause issues for self-signed certificates (bug 1122567, bug 1122666)

FIXED:
- Replied/forwarded icons disappear after folder repair, detach/delete (bug 840418)
- Attachment "Save As" files are displayed in Tools/Saved Files (bug 914517)
- Adding unknown email addresses to Mailing list, then deleting ghost duplicate entries from contacts pane, caused dataloss in mailing list (bug 628035)
- Web site from RSS feed was not rendered correctly (bug 662907)
- Email address with leading/trailing whitespace displayed wrongly with added quotes when composing ["foo"@bar.com] (bug 286760)
- Force display of Sender header if S/MIME sender is the signer (bug 332639)
- Addressing autocomplete widget: Typed text in red despite results/matches found if suggestions change by last input (bug 1042561)
- Status bar not accessible (bug 934875)
- Wrong folder may be deleted when requesting junk delete (bug 1018960)
- Severe UI stutter or freezes getting new mail for very large folders (bug 870556)
- Automatically rejoin multi-user conversations on reconnect for XMPP (bug 1014472)
- Various improvements when using IRC on moznet (bug 1083768 and others)
- Significantly improve XMPP support (bug 1085022 and others)
- Fixes for connecting to non-standard IRC networks (bug 870556 and others)
- Automatically reclaim IRC nicks during a reconnect (bug 1087566)
- Changing location in editor doesn't preserve the font when returning to end of text/line (bug 756984)
- Inline spell checker loses red underlines after a backspace is used (bug 1100966)