What if I have issued a CF6 using DoubleTime and then upgraded to 7.0.6. Will the CF6 change to a CF6R ?

No. Existing CF6 formatted Commitments will not change. There will be a grace period that will allow for both forms to be issued. 

NOTE: Once you have upgraded to DoubleTime 7.0.6, all new files will generate a CF6R Commitment.