It may come as an awful surprise, to find that the DWT format is independent of the DWG format mid-upgrade. This means if you save your template files as a 2010 DWT, older versions won't get it. You may have your options set to save as 2004, but that will not affect DWTs they will remain 2010.
If you find yourself in this situation, the best way I know to set things back (if you have mixed versions being used) is to open the template in 2010 and export it to AutoCAD. Pick the oldest version you need, but I go back to 2004 because it predates most AEC problems you might encounter otherwise. If you don't, you might get the error below when opened or used in older versions.
The Export to AutoCAD command creates a DWG file. You can now rename this file to a DWT in Windows Explorer or use the Save as function to create the new (old) DWT file you need.
I'm not sure any of that made sense.