4play was for updating channel maps on 4dtv units, and from what I understand problems arose due to fact that active channels would overwrite the map with current Motorola map, and all work would be lost.
It also requires a wiggler which is a bdm to usb cable to connect ird to a pc running 4 play front end.
Someone correct me if I am wrong. I have 4play but no wiggler (that don't sound right!!)
There is no version of 4play that currently operates with any of the maps in the 920/922/905. Changes were made to the channel maps making them incompatible with 4play sometime after July of 2003.
So you can use 4play with only a really old memory file from before the time something changed back then.
However: it may be possible to pick up any FTA digital channels by installing the 4play AFTER your battery dies and your 4dtv goes brain dead.
The biggest problem that 4play had, was that as soon as you tuned to a channel that was broadcasting consumer maps, the custom maps you made were overwritten and you had to start over again.
4Play would have to be completely re-written to be used with the current code written to the 4dtv receivers.