This is version 1.1rc of ARC.
**Recommended installation** is done by downloading below correct pre-compiled package for Windows, Mac or Linux 64-bit machines.
**Advanced** Linux and Mac users can also download the source, and compile C extension, following [Installation instructions](http://arc-alkali-rydberg-calculator.readthedocs.io/en/latest/installation.html#compiling-c-extension). For Windows users, we recommend using pre-compiled binary provided below. Please contact ARC developers if you have problems with that.