Paryushan Parva - Self Purification Festival
At the conclusion of the festival, the Sravakas request each other for forgiveness for all offenses committed during the last year. This occurs on the Paryusha day for the Swetambara and on Pratipada (first) of Ashwin Krashna for the Digambara.
What a great idea! Immediately I returned the email begging forgiveness myself for all of mistakes (known and unknown) that I might have committed against my friend!