Compiling Erlang from source
You can build Erlang from source on your own, following the building and installation instructions. Or use the Kerl script. Kerl is a script that lets you easily build Erlang with a few commands. Follow the instructions to build.
Source Versions and Windows Binaries for Patches
Information about all released OTP versions since OTP 17.0 can be found at the OTP Versions Tree page. This information includes a link to the GitHub source tag, and a link to the README. As of OTP 23, Windows binaries can also be downloaded from here for all patches.
Pre-built Binary Packages
Most OS package managers provide pre-built binary packages. You can also download the latest stable releases from Erlang Solutions. Erlang Solutions provides pre-built binary packages for OS X, Windows, Ubuntu, Debian, Fedora, CentOS, Raspbian and other operating systems.
Since OTP 18.0, Erlang/OTP is released under Apache License 2.0. The older releases prior to 18.0 were released under Erlang Public License (EPL), a derivative work of the Mozilla Public License (MPL).