The good news is that version 3.0.0 of the WIFI App on iOS fixed the horn problem with a TMCC diesel Lash-up. In general I had no problems running trains tonight, two DCS and the lash-up with nothing going crazy and trying fly off the layout. But when it came time to shut down, the TMCC Lash-up would not stop completely at a speed of ZERO (the 6 o'clock position on the speed dial). I had to move the pointer with the negative arrow to the 3 o'clock position to fully stop the consist.
So while the update propaganda said they added the DCS Explorer to the app, they didn't bother to report whatever else they did to it. This is never helpful. It's like they changed a bunch of stuff that they didn't tell us about for some reason. Look, all software developers do it, but it would just be nice if some of them didn't.