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Firefox Release Notes

Release Notes tell you what’s new in Firefox. As always, we welcome your feedback. You can also file a bug in Bugzilla or see the system requirements of this release.

56.0.1 Firefox Release

October 9, 2017

Version 56.0.1, first offered to Release channel users on October 9, 2017


  • Block D3D11 when using Intel drivers on Windows 7 systems with partial AVX support (bug 1403353)


  • Users of 32-bit Firefox on 64-bit Windows are migrated to 64-bit Firefox for increased stability and security.


  • Startup crash with RelevantKnowledge adware installed. Firefox Support has helpful instructions to remove it. (bug 1394550)

  • Startup crashes with 64-bit Firefox on Windows 7, for users of Lenovo's "OneKey Theater" software for IdeaPad laptops. To fix this crash, please re-install 32-bit Firefox. (bug 1369361)

  • Users running Firefox for Windows over a Remote Desktop Connection (RDP) may find that audio playback is disabled due to increased security restrictions. Learn how to mitigate this issue until it is corrected in an upcoming release.

  • Due to a bug in Mac OS X High Sierra, fullscreen mode has some issues (bug 1390125)

  • GSSAPI and Kerberos authentication do work in 64-Bit Windows Firefox. However it requires the advanced setting "network.negotiate-auth.gsslib" to contain the string "gssapi64.dll" because the default value (which is chosen if left empty) is wrong. Future versions of Firefox will contain a correct default value. (bug 1409275)

  • Some third party software (Comodo Internet Security, Kaspersky, Quick Heal Antivirus) are known to cause issues with Firefox 64-bit. These vendors have published new releases which addresses the issues. (bug 1407712)

  • Some older versions of the ATOK IME, including ATOK 2008 and 2009, can cause crashes or may not work on the Windows 64-bit version of Firefox. To fix those incompatibility issues, please use a newer version of ATOK or one of other IMEs. (bug 1409155)

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