Well, yes... but why can't you play on it???... I still don't understand... there's no valid reason... it's the same version as all the others with minor differences...
In The Restoration of Erathia (TRE), compared to Shades of Darkness (SOD), the magic, heroes, etc. have been changed. Therefore, players are not in the same conditions!!! And that is the main criterion for tournaments!
That is, a player (on TRE) taking another player's description (from SOD) may not be able to complete the game based on that description! And that is not allowed.
Sincerely.