Several security and stability issues have been fixed in this update:
Deal with bogus Turktrust certs MFSA 2013-20 Several memory security hazards fixed MFSA 2013-01 Updated OTS library to r95 to fix potential font-related exploits Security fix for libpixman stack buffer overflow Fix for certain types of input lag on Twitter/Facebook & other sites with unnecessary DOM invalidations Fix for HTTP pipelining re-use (improve pipelining logic) Performance&stability updates to cairo and direct2d back-end Improved performance for repeat gradients