Download //top\\ Firefox Old Version May 2026

[ Firefox 55.0.3 ] | Aug 17, 2017 • WebExtensions introduced • ⚠️ 9 known security issues [ Download ]

[ Firefox 56.0.2 ] | Oct 9, 2017 • Last version with full XUL/legacy add-on support • ⚠️ 12 known security issues • Windows 7+ / macOS 10.9+ / Linux [ Download (52 MB) ] [ SHA256 ▼ ] download firefox old version