In 2010, Mozilla's Mike Beltzner announced that the forthcoming Firefox 4 would not be released for Power Macintosh computers, compatibility with Mac OS X Tiger having already been removed, making Firefox 3.6 the last supported release of Firefox on the older architecture and platform. Mozilla stopped making PowerPC-compatible universal builds of Firefox 4 with beta 7. In response, developer Cameron Kaiser created a test build of Firefox 4 that could run on his Power Mac G5 at the same time as support was being withdrawn from beta 7. This was released to users in separate builds for AltiVec Macs and G3 Macs on November 8, 2010. Aligning with precedent that modified builds of Firefox source could not use Firefox trademarks without permission, the project was forked and named TenFourFox. A full complement of builds for the G3, the 7400 and 7450 G4 families and the G5 were released with beta 8 on December 15, 2010. JavaScript acceleration using its completed PowerPC version of TraceMonkey was released with beta 9 on January 12, 2011, and enabled fully for beta 11 on February 2, 2011. The finalized first release version, 4.0s, incorporated a security update and a fix for JavaScript performance, and was released on March 24, 2011. Version 5.0 switched to the current Mozilla rapid release framework, based on Firefox 5 and including additional AltiVec scaling and color features, and was released on June 16, 2011. After Mozilla announced the extended support release of Firefox, Cameron Kaiser stated that starting with version 10 of TenFourFox, stable releases of TenFourFox will be based on Firefox ESR to reduce maintenance burden. Between major ESR versions, developers tracked changes in Firefox's 6-week rapid release cycle with test builds only to determine whether or not they would still be able to build the software after the next ESR version was released. Only minor ESR updates were advertised as suitable for general consumption. In December 2015, Kaiser declared TenFourFox would move away directly from Firefox source code with 45 ESR, citing an inability to port later versions due to operating system and Rust compiler limitations. The first of the "Feature Parity Releases," or FPRs, in which major later Firefox features were backported to TenFourFox's modified Firefox ESR 45 base, was released after the official end of Firefox ESR 45 support on June 13, 2017. The TenFourFox FPR series of releases include additional later features as well as backported security patches from the most current supported Firefox ESR.
Features
TenFourFox shares its main feature set with Firefox along with optimizations for the PowerPC platform. Similar to other optimized build projects such as Pale Moon and Swiftfox, TenFourFox includes specific compiler optimizations to improve its overall performance and issues specific builds tuned for specific processor families. However, it also includes custom new features, in particular its JavaScript just-in-time compilation backend and AltiVec acceleration, and adds glue code to enable interface features from Firefox 4 and later to still work on Mac OS X Tiger. This has led to favorable reviews on its speed and performance on older Macintosh computers. Due to its compatibility with the older operating system, the browser lacks the bloated feature set of current Firefox versions. In particular, it does not fully support Core Text, so it does not understand Apple Advanced Typography features in certain international fonts; it does not support graphics acceleration for compositing; and it does not support WebGL. Furthermore, for security and maintainability reasons, NPAPI plugins support is deprecated, and has been subsequently removed.
