I believe mesh works over the 5ghz band. EAP-115 is 2.4ghz only so I dont think it will ever support mesh. 

In theory, MESH can work both on 2,4 and 5 GHz. The point is no vendor wants to make mesh on cheap 2,4Ghz devices. To tell the truth, I myself would not do it for eap115-wall, because this device is made for 1 bed hotel room, not a great coverage, so it will just not cover more than one room, so MESH will be useless.

EAP115 though is another question :)