Firefox Browser for Android
v4.0b3 · 13.4 MB · code 1
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File information
UpdatedNov 9, 2025
PublishedJan 7, 2021
Packageorg.mozilla.firefox
Versionv4.0b3 (1)
Size13.4 MB
MD5e51644f5c307b4074f2b5b667102da92
Min SDK5
ABIsarmeabi-v7a
Malware scanTRUSTED
Signature SHA192:0F:48:76:A6:A5:7B:4A:6A:2F:4C:CA:F6:5F:7D:29:CE:26:FF:2C
SignerCN=Release Engineering, OU=Release Engineering, O=Mozilla Corporation, L=Mountain View, ST=California, C=US
Total downloads500,000,000
This version500,000,000
DeveloperMozilla
Age ratingEveryone
What's new in v4.0b3
Thanks for choosing Firefox! Here's what's new:
- (144.0.1) Fixed an issue where the bottom toolbar could be hidden by the keyboard.
- Translations banner: see if a page is fully translated or still in progress.
- Tracking Protection: panel shows how your privacy is protected on each site you visit.
- Platform update: Firefox now requires Android 8 or later to ensure continuous improvements to performance and security.
Have feedback? Let us know at https://mzl.la/AndroidSupport.
- (144.0.1) Fixed an issue where the bottom toolbar could be hidden by the keyboard.
- Translations banner: see if a page is fully translated or still in progress.
- Tracking Protection: panel shows how your privacy is protected on each site you visit.
- Platform update: Firefox now requires Android 8 or later to ensure continuous improvements to performance and security.
Have feedback? Let us know at https://mzl.la/AndroidSupport.
Security scan
TRUSTED
- Developer signature verified 2025-11-09
- Signature SHA1 92:0F:48:76:A6:A5:7B:4A:6A:2F:4C:CA:F6:5F:7D:29:CE:26:FF:2C
- File MD5 e51644f5c307b4074f2b5b667102da92
How to install Firefox Browser for Android v4.0b3 on Android API 5+
Takes about 2 minutes. You'll need roughly 13.4 MB of free storage.
- Grab org.mozilla.firefox_1.apk — hit the Download button above (13.4 MB). If your browser warns about APK files, choose Keep or Download anyway — that warning fires on every APK, not just this one.
- Trust your browser to install — on Android 8+ go to Settings → Apps → Special access → Install unknown apps, pick the app you downloaded with (Chrome, Firefox, Files, etc.), and flip Allow from this source. On older Android, toggle Unknown sources under Security.
- (Optional) Verify the file — compute the MD5 of the downloaded APK and make sure it matches e51644f5c307b407…. Any difference means the file is corrupted or tampered — delete and re-download.
- Open the APK — tap the download notification, or find org.mozilla.firefox_1.apk in your Files app under Downloads, then tap it. Android's package installer will appear.
- Check the signer — the install screen will name the publisher. For this build it should read CN=Release Engineering, OU=Release Engineering, O=Mozilla Corporation, L=Mountain View, ST=California, C=US. If it doesn't match, cancel — you have the wrong file.
- Review permissions & tap Install — scroll the permission list, then confirm. If Play Protect flags it, tap Install anyway (this APK was scanned as TRUSTED).
- Done — open Firefox Browser for Android — tap Open on the install screen, or find the Firefox Browser for Android icon in your app drawer (this build targets armeabi-v7a devices).
Common install errors for Firefox Browser for Android
- "App not installed" — usually means an older or differently-signed version is already on your device. Uninstall it first, then retry. Your data may be lost unless you back it up.
- "Parse error" — the APK is for a newer Android than yours. This version needs Android API 5 or later. Pick an older build from the versions list below.
- "There was a problem parsing the package" — the download was interrupted. Delete the file and re-download over Wi-Fi.
- Works on one phone but not another — this build ships armeabi-v7a native code. Devices with a different CPU will reject it.