Form 1065, Schedules K-2 and K-3 are scheduled to be ready for e-file on March 20, 2022. Form 1120-S, Schedules K-2 and K-3 are scheduled to be ready for e-file Mid-June 2022.

More information from the IRS:

Schedules K-2 and K-3 Frequently Asked Questions (Forms 1065, 1120S, and 8865)

https://www.irs.gov/businesses/schedules-k-2-and-k-3-frequently-asked-questions-forms-1065-1120s-and-8865