Please notice that Flash Player 11 only supports 10.6 and newer. TenFourFox supports add-ons, but not plugins, that is, you can't use Flash at all. TenFourFox seems to be actively developed (version 17.0.3 was released Feb 16 2013). If you use a PowerPC processor you may want to try TenFourFox. OS X Leopard (10.5), or greater: 32-bit and 64-bit Intel If you use an Intel processor you can use Opera: Intel-based Mac: Opera (thanks to Cybermatatu for this one!) with older Flash 10.3 (beware, Flash 10.3 is an archived version and is no longer supported nor updated with security fixes by Adobe).
PowerPC-based Mac: TenFourFox and no Flash.