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Is Thunderbird still actively maintained and updated as of 2025?
Executive summary
Thunderbird is actively maintained in 2025: the project moved its Desktop release channel to a monthly “Release” channel in March 2025 with Thunderbird 136 as the new default, and team blog posts and product updates through 2025 (including work on Thunderbird Pro and mobile) show ongoing development and releases [1] [2] [3]. Release pages and beta notes indicate continued versioning into late 2025, including beta releases [4] [5].
1. Active development and a new monthly cadence — Thunderbird shifted to monthly releases in 2025
Thunderbird changed its release strategy in early 2025: the team announced that starting with version 136 in March 2025 the Desktop Release channel would become the default download and move Thunderbird to a monthly release cadence to deliver frequent feature updates and fixes [1] [2]. Coverage from How-To Geek and PCWorld frames that switch as a concrete sign the team intended to ship features and security fixes every month rather than relying only on an annual ESR cycle [2] [6].
2. Ongoing security and version releases — security fixes and ESR support
Reports around the 136 release noted that multiple security vulnerabilities were closed in that update and that the long-term ESR [7] continued to receive security updates through at least September 2025, indicating both active patching and parallel support for conservative enterprise users [6] [5]. The Thunderbird releases and release-notes pages remain populated (Releases, Release Notes, Beta Notes), showing a normal active-release lifecycle [8] [5] [4].
3. Beta and daily channels remain active — visible beta artifacts into late 2025
Thunderbird’s public beta notes show a 146 beta 2 released November 14, 2025, which demonstrates the project maintains multi-channel development (Daily/Beta/Release/ESR) and continues forward versioning beyond 136 [4]. The project’s “Daily, Beta, Release, ESR” model and visible beta pages are consistent with an actively maintained project pipeline [9] [10].
4. Product expansion and monetization signals — Thunderbird Pro and mobile work
Thunderbird has been expanding beyond the desktop client: the team has discussed Thunderbird Pro, a suite of paid, cloud-based services, and published updates (August 2025) describing planned features (500 GB starting storage, integration strategies, and a beta/mailing list) — evidence of ongoing investment and roadmap activity [3]. Thunderbird Mobile also moved forward: sources note a stable Android client launched in October 2024 and continued mobile releases through 2025 [11] [6].
5. Community and localization work — team blog activity and translator outreach
The Thunderbird blog and Mozilla localization posts document ongoing community and translation work and monthly development digests, indicating active engagement with contributors and translators in 2024–2025 as the project shifted processes for more frequent updates [12] [9] [13]. The blog archive includes development digests and product updates that demonstrate regular communication from the project team [12] [13].
6. What these signals mean — maintenance, feature work, and multiple viewpoints
Taken together, the move to monthly Release, visible security fixes and ESR support, beta channel activity, product expansion (Pro, mobile), and regular blog posts all point to Thunderbird being actively maintained and developed in 2025 [1] [2] [3] [4] [6]. Some reporting frames the change as a “new era” and a push to increase daily active installations on the Release channel, which suggests product-growth motives alongside technical maintenance [1] [2]. Alternative viewpoints — for example, users preferring ESR stability or worrying about commercialization — are present in the materials: ESR support continued into at least September 2025, and blog posts discuss opt-in aspects of paid services for users concerned about integration and privacy [6] [3].
7. Limitations and unanswered items in current reporting
Available sources do not mention specific staffing levels, long-term funding guarantees, or a comprehensive roadmap past the late-2025 notes; they also don’t provide independent audits of code velocity or community contributor counts (not found in current reporting). If you want confirmation about 2026 plans, explicit staffing or budgeting, or deeper telemetry on active installs beyond the cited goals and snapshots, those specifics are not present in the provided sources (not found in current reporting).
Summary: The sources show Thunderbird was actively maintained and receiving monthly releases, security patches, beta builds, and new product initiatives through 2025 — with explicit moves to increase Release-channel uptake and launches such as Thunderbird Pro and Mobile demonstrating continued investment [1] [2] [3] [4].