WotC will lift restrictions and allow stores to sell Prerelease Packs and Commander Decks for players to take home without participating in an in-store event. Organizers will then be able to enroll those players in an "At-Home Prerelease" in Wizards Event Reporter, and their attendance will count towards future allocations. Also, WotC will take a "snapshot" of retailers' Tickets, Engaged Players, and Activated Players as of the current time frame, and use that as a default for allocations of Promo Packs and exclusive products should the realtime numbers falter below that point during the health crisis.
Prerelease allocations, that would include numbers from Ikoria prereleases, will be based off of the highest prerelease attendance from the previous three sets. Additionally, WotC will apply a multiplier to each store's metrics to make sure stores receive adequate support.
Ikoria: Lair of Behemoths which is set to release on April 24, 2020 with prereleases scheduled to start on April 17 (see "Details Revealed For 'Magic: The Gathering' 'Ikoria: Lair of Behemoths' Product Line").