We have significantly decreased the amount of time it takes to upgrade Hero skills.
This will help allow everyone to quickly upgrade Heroes and try out other Heroes as well! To balance this for existing players, we have also given a bunch of speedups to players who have spent a long time upgrading their Heroes, as well as given a partial refund to players who have spent Skystones upgrading their Hero skills. Additionally, we have automatically completed all currently trained skills so players are able to immediately enjoy the faster training times. Cheers!