Try to save it out as a DXF and then open that DXF in 2015 and save it as a drawing template. You will have to relink any fields that reference anything in drawing or file properties.
Thanks GRF - tried it, lost all fields as you mentioned and lost all formatting. Not worth the effort to fix as I have access to 2017. I didn't want to convert all of the models to 2017 but it is what it is...
Dave
Contractin' Dave
Mechanical Design Engineer
25 years in the contracting world