I have a 2012 6.2 P1 Domane and a 2021 SLR7 P1 Domane. Other than frame geometry, there is very little comparison.
The newer bike is much smoother, has better wheels (Aeolus), 700 level carbon, hydraulic disc brakes, front and rear IsoDecoupler, tubeless 32mm tires. Both run the outstanding Di2 Ultegra groupset, the newer being an 11 speed rear.
My very positive experienced with the old one was the reason I bought the new one......These are true road endurance machines, bar none.
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Ride hard and ride on......