Firefox 16 was released on October 9, 2012.
Plans for this version called for fixing of bugs still outstanding involving support of new features in Mac OS X Lion, improvements to startup speed when a user wants to restore a previous session,[104] and support for viewing PDF files inline without a plugin.
Opus audio format is now enabled by default. Support for web apps was added.[105]
The roll-out of Firefox 16.0.0 was stopped on October 10, 2012, after Mozilla detected a security flaw and recommended downgrading to 15.0.1 until the issue[106] could be fixed. The security flaw was fixed in version 16.0.1, which was released the following day, October 11, 2012.[107] Version 16.0.2 was released October 26, 2012. It fixed additional security issues, and is also the final release to support Mac OS X Leopard.[108]