IdentityChanged

address presented an identity key that differs from the one pinned on first contact (see docs/identity-trust.md). Nothing was changed: the pin, any existing session and the local one-time prekeys stay as they were.

change names the pinned and the presented public identity key, so the application can show the change, compare SecureMessageClient.safetyNumber for it with the other device and, only if the user decides so, pass it to SecureMessageClient.acceptRemoteIdentityChange (docs/identity-verification.md). The presented key is unauthenticated: it is what the message or bundle claimed. The message text contains no key material.