In our upcoming 0.54.0 release we are going to deprecate three of our components: feature-session-bundling, ui-doorhanger and ui-progress. Primary classes of those components have been marked with the @Deprecated annotation. With 0.54.0 those components will still be released. However in a future release those components will be removed.


The feature-session-bundling provided the functionality for an early feature called “sessions” in the Fenix project. This feature has been replaced with “collections” and the functionality for this new feature is provided by the new feature-tab-collections component.


This component allowed apps to create “doorhangers” - floating heads-up popup that can be anchored to a view; like in Firefox for Android. This implementation was based on Android’s PopupWindow class. The implementation caused multiple layout issues and component using it (like feature-sitepermissions) switched to using DialogFragments instead.


The AnimatedProgressBar was first introduced in Firefox for Android and later used in Firefox Focus and Firefox Lite. A recent performance measurement revealed that the animation of the progress bar can have a negative impact on page load performance. While there was no noticeable difference on the latest high-end devices, on older devices, like a Nexus 5, we saw pages load about ~400ms slower.