If you have a Windows Phone and use Facebook, you will probably know that Microsoft makes the "first-party" Facebook app for Windows Phone, while Facebook provides an in-house build of their 'Messenger' app.
Microsoft maintains two builds, a stable and a beta. The beta version of the Facebook app has been pushed to version 5.3, and contains a list of improvements: an updated design, video upload, Messenger support, post detail page, photo commenting, ability to edit comments, tagging improvements, upload improvements, and lastly, performance improvements.
Beta apps in the mobile space (across companies and ecosystems) are generally not unstable most of the time, so if these features are something you've been missing, we recommend trying out the beta app (download link below). Let us know if you like it!