A voice engineer is setting up Cisco Jabber IM and must provide visibility for users not on their contact list. Which feature must be enabled to allow this visibility'?

Availability Sharing is the feature in Cisco IM and Presence Service Administration that controls whether users can share and view presence availability with others. When enabled at the system or user level, it permits presence subscriptions to users outside of an established contact list, making their online or offline status visible. Without this feature enabled, presence information remains restricted to users who have already been mutually added as contacts.

Ad-Hoc Presence Subscription refers to temporary presence subscriptions handled by the SIP stack and is a protocol-level mechanism, not the administrative feature used to grant broader visibility in Jabber.

Instant Messaging enables text chat functionality but does not control whether a user's availability or presence status is visible to others.

Offline Messaging allows messages to be stored and delivered when a user comes back online, which is unrelated to presence visibility for non-contact users.