22.1733GPPIP Multimedia Core Network Subsystem (IMS) Multimedia Telephony Service and supplementary servicesRelease 17Stage 1TS
It is considered useful to indicate to the user the current state, notably the activated state of those services which can lead to communications not being offered. For example, an active CFU results in no communication being presented.
Generally speaking any "not usual" state of a service should be indicated on the terminal: CFU activated, CW deactivated, OIR in permanent mode activated, etc.
In the case of services which can be remotely controlled from another terminal or a server, the terminal should receive this information from the network.