The developers of the Thunderbird email client have announced a change in their significant release model. Instead of the current scheme, where a significant release is formed once a year based on the ESR branches of Firefox, starting March 2025, they plan to release significant updates monthly, based on regular Firefox releases that have standard support timelines.
Since October of last year, Thunderbird has already started building versions based on regular Firefox releases, but these versions were not reflected on the download page, were positioned as test builds, and were accompanied by a special warning in the release notes. The current stable release of Thunderbird 128 was published in July 2024, and since then, only corrective updates have been generated for the 128.x branch each month. In March, alongside the corrective version 128.8.0 for the general public, Thunderbird 136 will be offered by default without a label indicating it's for testing purposes only.
Switching to a monthly significant release schedule will accelerate the delivery of new features to users, ease the transition to new major releases (changes will be spread over time), and broaden the range of bugs fixed in each update (the ESR branch only addressed vulnerabilities and critical issues).
According to the statistics gathered by the project, there are 10.5 million active installations of Thunderbird. By the end of the year, developers aim to increase the number of active installations of the monthly updated significant releases to 20%. Currently, the share of Thunderbird builds based on non-ESR Firefox releases is 0.27% (29,543).
Source: opennet.ru
