The current Firefox release is 158.0.1, first offered to Release channel users on 20 October 2026, according to Mozilla's release notes. It followed 158.0 on 13 October 2026. The 158.0.1 update blocks two compromised eMudhra intermediate certificates, fixes a Windows crash when printing or saving a page as PDF while a screen reader is running, and includes security fixes listed under advisory mfsa2026-111.
Firefox is free. The Windows download page names no price and calls the browser "billionaire-free and open source for over 20 years", and the page says "Firefox doesn't exploit your data and is backed by a people-first foundation." These are Mozilla's own statements.
Windows requirements
| Item | What Mozilla lists for Firefox 158.0.1 |
|---|---|
| Operating system | Windows 10 or later, 32-bit and 64-bit |
| Processor | 1 GHz or faster compatible processor or SoC |
| Memory | 1 GB RAM, or 2 GB RAM for the 64-bit version |
| Disk space | 500 MB |
Scope: Mozilla's system requirements page for 158.0.1, read 23 Oct 2026.
The Windows download page adds that Firefox is no longer supported on Windows 8.1 and below, and it points those users to Firefox ESR, offered in 64-bit or 32-bit builds. ESR is a separate extended support release, and the pages we read do not say how long it will keep supporting those systems.
Release history and cadence
| Version | Date | Headline changes from the release notes |
|---|---|---|
| 158.0.1 | 20 Oct 2026 | Certificate block-list update, Windows printing crash fix, security fixes |
| 158.0 | 13 Oct 2026 | Smart Window form-fill suggestions (gradual rollout), JPEG XL image support, several custom New Tab wallpapers, smoother scrolling |
| 157.0 | 29 Sep 2026 | Toolbar, sidebar and menu redesign called the biggest visual refresh in years; hardware AV1 decoding for WebRTC; warning when encryption key logging is on |
| 156.0 | 15 Sep 2026 | Release date only was read |
Computed from the dates above: 14 days from 156.0 to 157.0 and 14 days from 157.0 to 158.0, so major releases came every two weeks over this period. The first fix release, 158.0.1, followed 7 days after 158.0, and 158.0 was 10 days old on the check date of 23 Oct 2026.
The 158.0 notes also list translations for Albanian, Belarusian and Filipino. Firefox's own pages give no price for any feature, and an AI chatbot in the sidebar is advertised on the download page, with the claim that conversations stay between the user and their AI.
What the download page says about privacy
The page shows a tracking protection graphic but makes no technical claims on it, so this page cannot say what Firefox blocks by default. Mozilla's longer privacy documents would be the place to check, and they were not read for this listing. The release notes do show privacy-relevant fixes, such as the 158.0.1 certificate blocks that work even when Remote Settings is unavailable.
Enhanced Tracking Protection
Mozilla's support page explains the tracking protection that the download page only illustrates. Firefox uses Disconnect's list of known trackers to block social media trackers, cross-site tracking cookies, fingerprinters, cryptominers and tracking content in ads and videos. How much it blocks depends on the mode.
| Mode | What Mozilla's support page says |
|---|---|
| Standard (default) | Blocks social media trackers, cross-site tracking cookies, cryptominers and fingerprinters on all sites; tracking content is blocked only in Private Windows; Total Cookie Protection is on |
| Strict | Adds blocking of all cross-site cookies and tracking content in every window; Mozilla warns it can break login fields, forms, payments, comments and videos |
| Custom | You choose which trackers and scripts to block; WebCompat exceptions for specific sites exist from Firefox 142 |
Scope: Mozilla support, Enhanced Tracking Protection on desktop, read 23 Oct 2026. For a single site, the shield icon in the address bar turns protection off for that site and adds it to an exception list.
Before you install: a short check
- Confirm Windows 10 or later in Settings, then System, then About. Mozilla says Firefox is no longer supported on Windows 8.1 and below.
- If you are on an older system, the download page offers Firefox ESR in 32-bit or 64-bit builds. The pages read do not state how long ESR will continue for those systems, so ask Mozilla before relying on it.
- Check your memory. Mozilla lists 1 GB of RAM, or 2 GB for the 64-bit version, and 500 MB of disk space.
- Look at the sidebar chatbot setting if you do not want an AI assistant, since the download page advertises one.
Firefox updates itself, but the fix releases matter. The 158.0.1 update on 20 October blocked compromised certificates and carried security fixes, so a copy that has not updated since 158.0 is a week or more behind. Open the About Firefox window to see whether an update is waiting.
Alternatives in this directory
LibreWolf is a Firefox build with changed defaults and its own installer. Google Chrome, Microsoft Edge, Brave and Vivaldi run on Chromium, a different engine from Firefox's. Firefox's cache can be cleared by BleachBit, and BleachBit's own release notes show its cleaners being extended for other browsers as well.