The version of Scarlet previously distributed on Sourceforge was meant to be used
with JIRA 3.x and used Terracotta as clustering technology; this older version won't
be deleted but we encourage users to update to the new version.
Scarlet for JIRA 4 is totally revamped: it's now based on the LGPL licensed project Infinispan
and meant to work with JIRA 4.x.
Infinispan provides improved performance and lowers the cost, both as licensing fees and in terms
of numbers of machines needed for a running a reliable cluster.
The new version is currently not freely downloadable as it does patch the source code of Atlassian,
we didn't yet get permission to distribute this code, unless you're an Atlassian customer.
If you need to use Scarlet, drop us a note.