On November 20th, Firefox will end support for users operating Mac OS X 10.5 (Leopard). After this date, users will stop receiving Firefox updates, including new features and security fixes. If you are a Mac OS X 10.5 user and would like to continue to use the latest Firefox, you must upgrade to a computer running Mac OS X 10.6 or later.
Mozilla bases changes in supported operating systems on population size and trends, vendor support, testing resources, and technical feasibility. Ending support for Leopard will free up resources for new Mac features like Native Full Screen support and new Mac accessibility tools.
Over the next month, Firefox users running Mac OS X 10.5 will see prompts letting them know that they’ll no longer receive updates. Barring any major stability or security issues found over the next few weeks, Firefox 16.0 will be our last release to support 10.5.
After a five year run, it’s time for a big cat nap. Firefox support for Leopard ends on November 20th, 2012.