Can several accounts be used in the same app?¶

Yes. One installation can contain personal, work or alternative service identities, and the visible profile may not be the account behind a particular event or notification.

Identify every relevant identity precisely¶

Record provider account IDs, usernames, contact addresses, numbers, recovery details and current or cached profile state. Similar display names and copied photographs are not reliable identifiers. Provider and local records may show which account was active for an action.

Separate account, device and controller¶

One person may control several profiles, several people may share one, and accounts belonging to different users may coexist on a device. Ask which account caused the event, which installation or session was used and who controlled both at that time.

The app's presence alone answers none of those questions. Notifications may also combine several accounts without making the source obvious.