What table changes were made?
With all the new features that have been added to Extender 2013, the Extender tables had to change. Many of the tables are new with Extender 2013. While theory behind many of them are the same as previous releases of Extender, the actual SQL name of the tables are different as well as the structure of them is a little different.
With Extender 2010, most data records were tracked based on 3 fields, PT_Window_ID, PT_UD_Key, and PT_UD_Number. With Extender 2013, it is a little easier to track the data as it is based on two fields, Extender_Record_ID and Field_ID. Each resource you create in Extender will get a Record_ID attached to it and then the fields on that resource have a Field_ID attached to them.
With this, the data will no longer be linked based on the Key Fields setup on the resource. If the Keys need to be changed, they can be without affecting the data that has been entered into the system.