The /bookshelf command has never been part of the Offline KI. It was provided by the UAM KI plugin, which is no longer maintained and which unfortunately uses private API (programming interfaces) - which means it is hard to make certain changes to the Offline KI without breaking it. I spent some hours making sure that nothing is actually *broken* by using the UAM KI plugin with the current Offline KI (which already was a pain), but I will not even try to support its full functionality. Maybe you just don't have it installed anymore (my own UAM server does not offer the KI plugin), maybe it is broken.
To edit your shelf, have a look at ULMServerLinkBook.inf. The syntax should be rather self-explaining there are some hints at http://www.guildofwriters.org/wiki/Offl ... _the_shelf .