I am using V5.0 since I have no desire to use my cell phone for anything other than a phone. I too have had problems with lashups. My constantly used lashup has a GE EVO2010 running lead and a CSX412 with PS2 (I think?) running trail. The CSX has a new MTH battery. The PS3 EVO has more features than the PS2, and many of the lead EVO features "disappear" when I run in MU, like SXS. If I hit the reverse button on my remote, and then hit the forward button, the traveling lights on the EVO go out and there is no way to reset them using anything in the menu. (If I hit the reverse button, the ditch lights go out on the EVO but operate correctly on the PS2 CSX. When I hit the direction button again, the ditch lights in the EVO are not lit.) I use the "function save lashup" button each time but the consist still does not retain the settings. I also have had the problem of one loco starting up and the second engine "dead".
I also have two Mohawks. When I doublehead them, the variable whistle and some other features that are used for single locomotive operation "disappear".
I believe that MTH is severely underestimating how many of us run locomotives doubleheaded or in MU (i.e. lash ups).
I run with two TIU's in Super Mode and track signals are 8-10 everywhere on the layout. My two remotes have fresh batteries. I am sure that both TIU's and both remotes are V5.0 since they were upgraded by a MTH Service Center, at a cost.....
My general experience with software upgrades is that in a number of cases the upgrade solved one set of problems but created others, and that is my opinion and one reason that I won't sign up for an upgrade whenever one is announced.
I do not have a tablet and the location of my desktop computer and the layout and its power supplies make it impractical to do my own downloads, so I have just elected to put up with the idiosyncrasies. I do find that I am running my layout less and less...
