About
Phyrox ESR portable app made with
Portapps.
Run Mozilla Firefox ESR as a portable app.
| Latest version | 128.9.0 |
| Internal release | 65 |
| Last updated | 2025/04/06 |
| Links | |
| Maintainer | CrazyMax |
| Homepage | https://www.mozilla.org/en-US/firefox/organizations |
| License | Mozilla Public License 2.0 |
| Changelog | CHANGELOG.md |
Installation
Download and install the latest portable setup where you want then run phyrox-esr-portable.exe.
If you have already installed Firefox ESR from the original setup, move the following files :
%APPDATA%\Mozilla\Firefox\Profiles\*.default\*todata\profile\default
Then run phyrox-esr-portable.exe and remove Firefox ESR from your computer.
Upgrade
For an upgrade, simply download and install the latest portable setup.
Infos

Following a trademark violation report (#5) from Mozilla, Firefox ESR portable has been named Phyrox ESR portable on Portapps. Nothing changes except its name.
Standard and Developer Edition are also available
Modifications
Some modifications have been made through policies to ensure portability:
- Multilingual : All languages are included in
app\langsand can be enabled in config file (see below). - Disable updater : Firefox ESR updates are turned off.
- Don’t check default browser : Stops Firefox ESR from checking if it is the default browser at startup.
- ‘Know your rights’: Don’t show on first run.
- WhatsNew: Don’t show WhatsNew on first run after every update.
- Profile: Profile path is overrided to
data\profilefolder (see below). - A shortcut is created at launch to allow native notifications and removed when Firefox is closed
Configuration
Phyrox ESR portable can be configured through the main YAML configuration file:
app:
profile: default
multiple_instances: false
locale: en-US
cleanup: false
profile: Name of the profile created indata\profile\<name>(defaultdefault)multiple_instances: Allow multiple instances (defaultfalse)disable_telemetry: If enabled, Firefox ESR telemetry is not uploaded (defaultfalse)disable_firefox_studies: If enabled, Firefox ESR will never run SHIELD studies or do Heartbeat surveys. (defaultfalse)locale: Locale located inapp\langscan be used to change UI language without.xpiextension (defaulten-US).cleanup: Cleanup leftover folders (defaultfalse)
Policies
You can use custom policies by creating data/policies.json file like this one:
{
"policies": {
"DisableFirefoxStudies": true,
"DisableTelemetry": true
}
}
DisableAppUpdateandDontCheckDefaultBrowserare forced totrue.
Known issues
There is no known issues
Please let us know if you found one!
Download
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Otherwise you can download directly from the releases page on GitHub.