Mozilla Firefox Quantum V66.0.5 Apr 2026

As part of the broader Firefox 66 release, this version includes:

A new ability to search through all open tabs via the tab overflow menu. Mozilla Firefox Quantum v66.0.5

Prevents web pages from "jumping" while images and advertisements load. As part of the broader Firefox 66 release,

Mozilla Firefox Quantum v66.0.5, released on May 7, 2019, was a critical point update primarily focused on resolving a significant bug that caused browser extensions to be disabled. released on May 7

Automatically prevents websites from playing sound-enabled media.

Allows users to authenticate on websites using facial recognition or fingerprints on Windows 10. System Requirements Firefox 66.0.5 System Requirements