Other sources of Thunderbird information

Introductory help

• Thunderbird 3.1 FLOSS manual, most current, unofficial manual
• Managing Thunderbird mail accounts at gunnars.net (2.0 and earlier)

Support

• MozillaZine Thunderbird support forum
• SUMO (Official Mozilla support/KB articles for Thunderbird)
• Thunderbird support newsgroup or via google, Thunderbird support newsgroup
• mozilla.dev.apps.thunderbird
• Thunderbird Portable support forum (USB flash drive based version of Thunderbird)
• Thunderbird category on Discourse
• Questions on SuperUser tagged Thunderbird (not a dedicated forum, but useful).
• r/Thunderbird on reddit (limited usefulness due to low traffic)

Non-English forums

• Mozilla.cz fórum (Czech)
• MozBrowser nl-be (Dutch)
• GeckoZone (French)
• Thunderbird Mail DE (German)
• Mozilla.org.il חדשות (Hebrew)
• Mozilla Italia (Italian)
• MozillaZine (Japanese)
• Mozilla Россия (Russian)
• MozillaES (Spanish)

Add-on Guides and github based repositories

• Thundernest is the repository for the MailExtension Documentation, WebExtension Experiments, server side issues etc.
• Mozilla Developer Network
• Add-ons guide for version 57 - 60
• Add-ons guide for version 63
• Upgrading add-ons for 68
• Thunderbird cross-reference (search source code)
• Legacy API + WebExtensions API
• thundernest/developer-docs

Official blogs

• Planet Thunderbird
• Mozilla Add-ons blog
• Mozilla Thunderbird Blog

Bug reports

• Mozilla Bugzilla (Thunderbird bug reports)
• Thundernest (Thunderbird.net bug reports)

Other

• A list of Thunderbird communication channels
• BabelZilla (localization support forum for add-ons)
• Calendar weblog (Lightning)
• Known vulnerabilities in Mozilla products
• Rumbling Edge It is currently inactive but used to be the best way to track what got fixed.
• Mozilla Downloads is an archive of old projects such as the Grendel mail client and the Netscape Messaging Access SDK which use earlier versions of the mail/news code used by Thunderbird.
• Mozilla Error Lookup
• Mozilla Localization (L10n)
• Postbox knowledge base. Postbox has a different GUI and features but has enough in common (since its based on Thunderbird) that some of the articles might be useful.
• tb-enterprise is a mailing list for administrators of large enterprises.
• Thunderbird Enterprise information for administrators of large enterprises.
• The Differences between SeaMonkey and Firefox/Thunderbird
• Thunderbird page in Mozilla Wiki
• Thunderbird:Backend Hacking Guide For Newbies
• Wikipedia article on Thunderbird

Build status

Thunderbird is a volunteer project involving many moving parts, people and issues, so it does not have a fixed, dated release schedule. Releases occur at some point after Firefox releases, on a best effort basis. When you see it mentioned in release notes and in automatic update then you can be reasonably certain it is officially released - other sources of information generally cannot be trusted to be accurate.

• Releases (MozillaWiki page for for tracking in-progress releases)
• An explanation about versions and builds for testing...
• Thunderbird infrastructure.
• Pushlog for try server (current test)
• Viewing and searching Mozilla source code online

Status

• Thunderbird project page
• Features being evaluated or worked on (seems obsolete, but provides a useful history)
• Mozilla releases
• Thunderbird status meetings

Development Plans

• Mail/News (used by both Thunderbird and SeaMonkey)
• Tb-planning is a moderated mailing list to "offer an easy, transparent venue for getting constructive, Thunderbird-related work done".
• Maildev is a moderated mailing list for Thunderbird Engineering Council plans
• TB59 support issues
• Near term focus (2019)
• Are most of the existing add-ons being sacrificed due to adding support for WebExtension?
• Meta - Add support for WebExtensions
• Deal with the fallout of bug 1413413 (see below)
• Remove support for extensions having their own prefs file
• Remove support for non-bootstrapped extensions

Specifications

Most of these specifications were written for Thunderbird 3.x or earlier.

• AutoComplete
• AutoConfiguration
• Code review requirements . It also lists who is responsible for each sub-module.
• Encryption technologies
• Gloda
• HTML Sanitizer
• HTTP extensions for Account Management and Session Identification
• LDAP support
• Mail UE Specs
• Mail/News Engineering page
• Mail/News Related Standards
• Message Reader
• Message Threading
• Network Security Services (NSS)
• NSS shared database
• SSL error codes
• Pluggable mail stores
• Maildir
• Thunderbird 3 for developers
• Thunderbird 3.1 for developers
• Text to HTML conversion
• Using the Multiple Accounts API
• X-Mozilla-Status explained

https://developer.mozilla.org/Special:Tags?tag=Thunderbird lists all of the pages tagged with Thunderbird on the MDC web site