Many JCR clients use the optional versioning feature, so it would be great to add support for this. See the Section 8.2 of the JCR 1.0 spec [1], or Section 15 of the JCR 2.0 spec [2]. There is also some example code showing the basics of how to use versioning [3].

This task should also include adding a small section to the Reference Guide to describe how versioning can be used.

[1] http://www.day.com/specs/jcr/1.0/8.2_Versioning.html
[2] http://www.day.com/specs/jcr/2.0/15_Versioning.html
[3] http://wiki.apache.org/jackrabbit/ExamplesPage#Versioning_Basics