Bottomline: Smithers’ releases are top notch, no matter what version of OpenELEC they’re including!
You can update it for yourself if you want. I did it with his previous 14.2 triple build and upgraded it to 15.2 without any problems. All you have to do is download the “update file .tar” (not image) for openelec and ssh into the pi and place it into the “/storage/.update” folder and then restart the pi and it will update. I have not done it with this latest build so can’t say how it will turn out.