Mozilla release the next update to Firefox on Tuesday, September 22nd with Firefox 41.0. This release included many fixes, updates and changes which can be reviewed in the release notes. Also note:
- Extension Signing Validation can still be disabled in this version by changing xpinstall.signatures.required to False in about:config.
- There is not an official Windows 64-bit (Win64) version of Firefox 41, this is currently planned for Firefox 42.
User should be prompted to update or can do so manually via Help > About Firefox or download and install the latest version via getfirefox.com. The next planned release is Firefox 42 on November 3rd.