what aircraft have scimitar winglets?

[CupCrusher40]

are they put on at 4 year heavy checks or not fitable on the old Boeing wing?

Were they cross wind tested if the bottom  of it hits the runway?

[dfwskier]

Southwest flies three types of aircraft :737-700, 737-800, 737 Max8.  All three type have split scimitars (not sure if all 700s have been retrofitted yet).

The FAA would not have certified the use of them if there was a concern about their use at any point in time of the flight envelope - including cross wind landings.

[MottStreet]

Split Scimitar Winglets are offered by APB for the 737-800 and 737-900ER and came into service in early 2014. They are available as a retrofit to existing winglet aircraft.