How to change the number of versions kept?

Version configuration

By default maximum versions allowed is set to 10, you can change this anytime. To do so, login as user with access to configuration and set the maxVersions property under server -> version

Please note : previous versions created before setting new maximum version index will not be effected until new version is created for a perticular node. For instance node 'A' has 10 versions and you change the max version index to 2, you will still see all 10 versions until the next version, once node 'A' is versioned again all previous 9 versions will be removed.