Can I do mass update relations in card?
Yes, you must enable it in the Administration Module, in a general way (paragraph 29.1.3 of the Administration Manual 3.3) or on individual classes (paragraph 20.2.1 of the same manual) and then find the function in the context menu of the specific class.
hm, I selected 3 VMs, click to Edit selected Items, and I can select only card attribute’s, not relations.
Excuse me, I understood the relationships linked to reference attributes.
No, a massive update of other types of relationships is not possible.