Link related Rules in Bandai Official Ruling
In BT21, Bandai introduced new type of Digimon, Appmon. These series of Digimon give a new effect called "Link".
Below are guideline from official website about this new ruling.
Link DP, Link Limit and more info:
App Fusion ruling:
What happens to a digimons link card if it digivolves into a digimon without the appmon trait?
In that case, the link cards will be trashed.