5 Star pop to 6 Star?

[4am]

I've bought several 6 star players and had them drop to a 5 star, and pop back up to 6 stars again.

That will only happen if you have a six star player and are subsequently promoted. Further training could see them return to six stars.

I've also bought many many 5 star players, but have never managed to get them to go 6 star.

How old are they? Their stats won't improve a great deal once they hit 26.

Does that mean they cannot?

No.

I buy a 5 star at the start of the season, plays every game (sometimes 3 in one day), never ever goes up to 6 star, but other players I paid 50 tokens for, go down and have gone up again.

The younger they are, the better they will develop. 18-21 y/o's improve the quickest, then 22-25.

Cheers, best game in the world by the way...

Each to their own!