Csound version 6 provides significant advances in functionality over
version 5, not only for the Csound application, but also for the Csound
library and application programming interface (API). Complete backward
compatibility has been retained for all orc/sco/csd based works, but changes
in the API are not backwardly compatible.

Csound Sources

[Csound @ SourceForge] – Current/Previous releases

[SourceForge Git Repository]

Instructions for using Git by Steven Yi
Using git for for just checking out and compiling is pretty easy.
1. Install git
2. Use this command to clone the Csound6 git repository:
git clone git://
This will checkout a read-only (meaning, you can not commit back to
the central git repository) version of the Csound5 repo.
3. To update with the latest from the master repo, use:
git pull
4. The same process is used for the Csound manual. Use this command to
clone: git clone git://
More information on how to use GitHub:  Git Cheat Sheet