Changes

Every day, Mozilla developers write code that is merged into a common code repository (mozilla-central) and every day that code is compiled so as to create a pre-release version of Firefox based on this code for testing purposes, this is what we call a Nightly build. Once this code matures, it is merged into stabilization repositories (Aurora, also known as Beta and Dev Edition, and later Beta) where that code will be polished until we reach a level of quality that allows us to ship a new final version of Firefox to hundreds of millions of people. This development process used to ship a new version of Firefox every 5 to 8 weeks is called the Train Model. 

|+ style="font-weight: bold;" |Firefox channels as of March until April 18, 2017