If you have a 2013, Ford says E-15 is OK.
Mixed with straight gas..
3 gallons E-85 added(13.4%) 91 users get 93 octane and better charge cooling.
3 gallons E-85 added(13.4%) 93 users get 95 octane and better charge cooling.
For states with oxygenated gas..(I have no experience with this)
1.25 gallons added gets you to 15 % but one octane point less for both 91 and 93
The LPFP is different on the 2013, other than that there is no change between gen 4.1 and 4.2