| Windows version |
Firefox version |
Notes |
|---|---|---|
| NT 3.51, 95 | 1.5 | Only works partially on NT 3.51 |
| NT4, 98, Me | 2 | Wikipedia 2.0 system requirements 3.0 system requirements |
| 2000, XP SP1 | 12 | Support was cut off at FF13, but the last ESR version was 10.0.12, released on 2013/01/08, the same day as FF18. Source This no longer happens with later cutoffs, as they always happen immediately after an ESR. |
| XP SP2 ~ Vista | 52esr | 32bit versions only. Source |
| 7 ~ 8.1 | 115esr | Source 1 Source 2 Lifespan for 115esr is extended |
| Starting version | UI name |
|---|---|
| 4 | Strata |
| 29 | Australis |
| 57 | Photon |
| 89 | Proton |
| ? | Nova |
The "Nova" UI is still in development as of April 2026. (Sources: Sören Hentzschel (German), OMGUbuntu)
4 was the last version before Firefox transitioned to a rapid release schedule like that of Chrome. (Sources: Ars Technica, Mozilla Wiki)
52 ESR was the last version to support NPAPI plugins other than Flash. Note that the non-ESR version of 52 dropped support, but support remains in 52 ESR. (Sources: Mozilla support, Java.com help)
56 was the last version with XUL extensions support.
84 was the last version with Flash support. Source
Because new UI designs waste too much space.
GitHub: e3kskoy7wqk/Firefox-for-windows-7
(Pale Moon, Basilisk, and further forks of these)
Pale Moon has the FF4~28 look (Strata), while Basilisk has the FF29~56 look (Australis).
roytam's forks "New Moon" (fork of Pale Moon 28) and "Serpent" (fork of Basilisk 55) support XP. (Blog, MSFN thread, Downloads)
roytam also has a fork of Pale Moon 26.5 for Windows 2000. Downloads
Some time after the WebExtensions apocalypse, Waterfox separated into two branches, Current and Classic. Both were updated until Waterfox Classic's discontinuation with version 2022.11. Waterfox Current later dropped the "Current" name and became known as just Waterfox.
What I like about Waterfox is that by default it uses the "compact" UI density, and also makes other adjustments (built-in userChrome.css changes?) to make the tab bar compact.
According to GitHub issue #3609, the last version of Waterfox to support Windows 7~8.1 is 6.0.20, based on Firefox 115.
e3kskoy7wqk's mod based on Firefox 140.8.0 works on Windows 7.
adeii's mod of 6.6.9 works on Windows 8.
Last update was version 2022.11. Based on Firefox 56. Has WebExtensions support (UXP doesn't). Has the Australis look.
Prior to the split of Current and Classic, it was just called "Waterfox". The last version to support XP and Vista is 52.0.2. Later versions require Windows 7.
I used it for a while when FF57 was just released, to take refuge from the WebExtension apocalypse, but now I don't see a point in using it any more. Waterfox Classic hadn't been keeping up with the modern web for some time even before it was discontinued. For WebExtensions just use the latest Firefox. For Australis just use Basilisk.
A browser that works on XP, the current MyPal is based on Firefox 68.
An older bearer of the MyPal name was based on Pale Moon.
A project led by Matt A. Tobin who used to be associated with the Pale Moon team. Used to work on UXP projects, but stopped as of 2024. Programs made included "Interlink" (UXP Thunderbird fork) and "Borealis Navigator" (UXP Firefox fork), though builds were only available for the former. roytam has for-WinXP forks of both.
Nocturne is a fork of r3dfox that restores removed Firefox CSS customization options, keeps Windows 7 and 8 support alive, and targets customized Windows 10/11 builds.
Latest Releases for Legacy Platforms
Also has a fork by roytam, but seems to be abandoned since December 2024.
Latest official version as of February 2025 still supports XP SP3. It's possible to run K-Meleon 76 on Windows XP SP2 using a kernel replacement. (Details on forum)