Question: In an Inter-UE Transfer scenario within IMS, what is a prerequisite for Collaborative Session Control to be transferred between two UEs registering Public User Identities?
Option 1: The UEs must register Public User Identities that share the same service profile (and thus belong to the same IMS subscription).
Option 2: The UEs can have any type of subscription and service profile, as this does not affect Collaborative Session Control transfer.
Option 3: At least one UE must be roaming on a different network, and both UEs need to support an additional, specific Inter-UE Transfer feature.
Option 4: The transfer is only possible if the UEs belong to different operators but have the same service profile.
Explanation: This is correct because, according to the assumptions for Inter-UE Transfer, Collaborative Session Control can be transferred between UEs that register Public User Identities sharing the same service profile, indicating they belong to the same IMS subscription. This ensures continuity and consistency in service experience during the transfer.