Facebook has never paid too much attention to the guidelines of Android, to say the least, but lately it seems that something is changing, Facebook is taking small steps and want to adapt to the Material Design.
The back button is now turned in the FAB , the button located on the bottom right that allows you to write a new post, take a picture, upload a photo or even record your own position. The implementation is very similar to that of Inbox to understand, considering that if the pressed key expands to show other options.
A great step forward in short, that we hope will be followed by many others from Facebook. This change is server side or not all the people can see this change but if you want to try it (as we have just said could be a random rollout) you'll have to follow these steps or just download this apk:
Tags
Android
Android App
Android Lollipop
Facebook
Facebook Update
Material Design
Material Design App