Firefox 140 launches as ESR with vertical tab updates and memory-saving tools

Mozilla Firefox 140 is now available as a regular update and the latest Extended Support Release (ESR), introducing updates to existing features and stability enhancements. The update improves the vertical tabs feature by making the pinned section resizable, allowing users to adjust the number of visible pinned tabs in both collapsed and expanded views.

A new “Unload Tab” option lets users manually pause background activity for any tab without closing it, helping reduce memory and CPU usage. The tab reloads when revisited, working like a temporary bookmark. The update also improves full-page translations by prioritizing visible content.

Users can now add custom search engines by right-clicking on a search field and select “Add Search Engine”, or manually configuring them in Settings Search Add (below the search shortcuts table) to manually enter a search URL. Additional updates include address autofill for Italy, Poland, and Austria; a built-in Arabic spellcheck dictionary; the option to remove the extensions toolbar button; and a cleaner New Tab interface.