The most recent Android update to FltPlan Go will not connect to a Stratus 3 so the only way to unlock and use GDL90 is to use an Apple device. Unfortunately it will then revert to non-GDL90 if it sees an Apple WiFi connection which is easy to do on a busy ramp or with a pax using an iPhone.
I'm in communications with Stratus and they have confirmed the problem and communicated it to both FltPlan Go and IFly GPS, Stratus, who advertises the 3 as Open GDL90 compliant acts like it's not their problem and are waiting for FltPlan Go and IFly GPS to solve the problem................meanwhile I...........and no doubt others..........have $700. paperweights.