PER: After your final eligibility review is complete at CIO, if successful, you will receive confirmation of Positive Eligibility Review (PER).
If you specified an email in your application then CIO will send this to you by email, since this is cheaper for them and quicker for the applicant.
AOR: Acknowledgement of Receipt. It means your file is received at visa office and is put in a queue to be reviewed by visa officer and if found eligible it will undergo further processing.
Yes, both by email. In my experience, AOR first then PER. Others, PER immediately without AOR.
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