Thunderbird 5.0 - New Features and Changes
- This article is inherently incomplete and subject to change until TB 5.0 is released.
- Make sure you understand that pre-release versions may be stable enough for your purpose but equally well may corrupt your e-mail or entire system when running into bugs!
- Do not use pre-release versions in production environments where data loss or instability matters!
- See Testing pre-release versions on how to stay on the safe side before looking into the release candidates.
Thunderbird 5.0 has just issued its first beta release and the final release is coming up soon! Don't be fooled by the version number. While the changes from 2.0 to 3.0 were substantial, this is a rather incremental release, comparable to 3.1 versus 3.0. Thus, Everything in Thunderbird 3.1 - New Features and Changes and also Thunderbird 3.0 - New Features and Changes should still be valid unless obsoleted here.
What happened to Thunderbird 4.0?
In a process driven by the Firefox developers, Mozilla has substantially redesigned their release process. Thus, there will no longer be parallel branches after Firefox 3.6 and Thunderbird 3.1 have reached their end of support. Instead, each release will have a full version bump even if there are no or marginal feature changes (i.e., Firefox 5.0 will be the stability update for 4.0.1, then 6.0 will be the update for 5.0, etc.) [1]. Only in quick "firedrill" follow-up releases which become necessary shortly after a release to fix a missed issue, a minor "dot" release will be issued.
Thunderbird decided to follow that pattern, and in the process re-aling its numbers with Firefox again [2]. Consequently, the "Miramar" branch has been bumped from 3.3 to 5.0, and the next release after 5.0 will be Thunderbird 6.0 around the same time when Firefox 6.0 is released. It yet has to be seen how this process turns out in practical terms, especially with respect to add-on compatibility as a stable API is no longer given as it was previously assured during the lifetime of a branch.
Changes in supported platforms
New appearance on Vista and Windows 7
New default theme
Detailed discussion moved to Thunderbird 3.0 - New Features and Changes/Themes
Font rendering issues
gfx.direct2d.disabled
Account setup
New account wizard
More archive options
- mail.identity.default.archive_enabled
- mail.identity.default.archive_granularity
- mail.identity.default.archive_keep_folder_structure
Attachment pane redesign
Show first row of attachments only by default, then allow opening with toggle:
#attachmentView > [collapsed="true"] {
visibility: visible !important;
overflow: auto !important;
}
Always open, toggle removed:
#attachmentView > [collapsed="true"] {
visibility: visible !important;
}
#attachmentToggle {
display: none !important;
}
Advanced options
Signature delimiter
mail.identity.default.suppress_signature_separator
Display of large message/attachment sizes
chrome%3A//messenger/locale/messenger.properties#megaByteAbbreviation2=***%.*f MB
New add-ons manager
extensions.getAddons.cache.enabled
