DNN 05.06.01 made some changes to the way viewstate is handled and this broke the licensing screen callbacks. So the automatic activation buttons threw an error. Only manual activation continued to work.
Other than that most effort at this moment is going to DMX 6. Expect quite a few changes. It is also the moment to clean up and reshuffle the API. DMX 6 will likely necessitate recompiling most extensions.
But now to this release. Over the past Month a number of issues cropped up that have been resolved in this release. For a full list check out this post:
http://www.bring2mind.net/Support/Forums/tabid/143/afv/topic/aff/26/aft/8237/Default.aspx
Find the module through the download link on this site or your regular distribution channel.
Peter