Debuted the Proton UI , featuring "floating" tabs, streamlined menus, and a more cohesive, calmer visual palette.

Launched "Enhanced Cookie Confidentiality" and a new download interface.

If you need a specific version between 87 and 104 for testing or compatibility, you should only use official Mozilla sources to ensure the installers haven't been tampered with. Firefox 104.0, See All New Features, Updates and Fixes

Introduced "SmartBlock" for private browsing and simplified the Web Developer menu.

This era of Firefox development (March 2021 to August 2022) focused on modernizing the browsing experience and enhancing performance on modern hardware like Apple Silicon.

Mozilla Firefox versions 87 through 104 represent a major transformative period for the browser, headlined by the introduction of the "Proton" user interface and significant privacy upgrades like Total Cookie Protection. Release Timeline & Significant Milestones

Introduced RLBox , a sandboxing technology to protect against malicious sub-components.

A landmark version that added Picture-in-Picture subtitles and improved scrollbars on Linux and Windows 11.