DigiVolution

Digivultion happens when your digimon meets the specific standards for it.

These standards are their Hp,Energy,Age,Level,Defence,Attack,S.Attack,S.Defence and speed.

These requirements are important and if you think you are able to digivolve and can't make sure all your digimons specific stander and you didn't miss out on one of its stats. You can check the stats in the digimon stats by Shift-RightClicking on the digimon with the Digivice and then clicking stats.There you'll see all the digimon stats age Energy,Hp,Xp level and stats.

The heart and the bar next to it shows the Hp.The E below it shows the energy level and the meat on a bone bar below it shows the hunger level of the digimon.

Also you can check roughly the digimons Hp,Energy and Hunger bar on the digimon by having a Digivice in your hand of your hot bar.