In Firefox 65 we intend to ship two new features to help prevent user frustration caused by using profiles created by newer versions of Firefox.
Why Firefox stores all of its settings in the user’s profile and unless certain command line arguments are used Firefox always launches with the same profile. Periodically as Firefox upgrades it makes changes to the settings that can render the profile unusable by earlier versions of Firefox. This can cause anything from certain features of Firefox being broken after a downgrade to Firefox crashing on startup. To protect against this two new features will be landing in Nightly soon. Dedicated Profiles Per Install A common cause of users switching between different versions of Firefox is having Firefox installed multiple times. This most often happens when users have different channels installed at the same time like ESR and Release. It is a common request to be able to run the different installs at the same time. In Firefox 35 this was made possible for the developer edition by giving it a dedicated profile. The new dedicated profiles per install feature extends this and will give every install of Firefox on the computer a dedicated profile by default. Users will be able to run different installs of Firefox simultaneously. Each will use a different profile for its settings. Upgrading an install of Firefox will keep it using the same settings. We’re tracking work on this feature in bug 1474285. Profile Downgrade Protection For cases where users manually downgrade an install of Firefox or attempt to forcefully use an older version of Firefox with a newer profile the profile downgrade protection feature will now tell the user that the profile is too new to use with this Firefox giving them the option to create a new profile to use or to quit. We’re tracking work on this feature in bug 1455707. Developer Implications As developers it is quite common to switch between different builds for example when testing different built versions of Firefox and doing regression testing. To support these use-cases a new command line argument “--allow-downgrade” will allow skipping the downgrade protection. Conclusions While some users may be impacted by this change we believe that most users will be unaffected and those that are will see less problems caused by downgrades than previously. This will give us the ability to ignore the possibility of downgrades when implementing new features and fixing bugs going forwards. Being able to make the assumption that this code works as designed will allow us flexibility in other changes downstream. _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
