Terracotta can be downloaded from the Terracotta website under the download section.

Servoy integrates with the Open Source edition of Terracotta and is tested against the "Terracotta 3.1.1 and Ehcache 1.7.0" release.

The following link provides a direct link to the download of the "Terracotta 3.1.1 and Ehcache 1.7.0" cross platform binary: click here