You should update your RBS collection to version 2.7. Otherwise, if you use iManager to access a tree that has an RBS collection from a previous version of iManager 2.x, you won't see all of the roles and tasks that should display.
In the Configure view, click Role Based Services > RBS Configuration.
Click the link in the Out-of-Date column for a module that needs updating.
On the Out-Of-Date Modules page, select a module, then click Update.
A message appears that confirms a successful update.
Updated plug-ins are visible in all versions of iManager 2.x.