Mozilla has officially released Firefox 71 for Windows, Mac, and Linux. With it comes support for the picture-in-picture API and improvements to the Enhanced Tracking Protection feature and the Lockwise password manager. With the release of Firefox 71, the other development branches of Firefox have also moved up a version. This brings Firefox Beta to version 72 and the Nightly builds to version 73. With this release, Firefox Beta and Nightly have moved up from version 72 to version 71. The full change log can be read here.
Source: https://www.bleepingcomputer.com/news/software/firefox-71-released-with-picture-in-picture-support-and-more/