For the detailed information about building and developing Netty, please visit [the developer guide](http://netty.io/wiki/developer-guide.html). This page only gives very basic information.
[The 'master' branch](https://github.com/netty/netty/tree/master) is where the development of the latest major version lives on. The development of all other major versions takes place in each branch whose name is identical to its major version number. For example, the development of 3.x and 4.x resides in [the branch '3'](https://github.com/netty/netty/tree/3) and [the branch '4'](https://github.com/netty/netty/tree/4) respectively.