mod_invites_register: Fix missing 'from' attribute (thanks Martin) This should probably cause a noisier error in Prosody, than the current > No hosts[from_host] (please report): <stanza> A stack trace would have been useful, for example.

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summary: Allow server administrators to probe any user
...

This module lets server administrators send `<presence type="probe"/>`
to any local user and receive their presence in response, bypassing
roster checks.