On November 16, 2021, the IRS published DRAFT 2021 Instructions for Form 1042, Annual Withholding Tax Return for U.S. Source Income of Foreign Persons. The DRAFT Instructions include subtle changes and updates for the 2021 tax year. One clarifying edit to Line 63d is that it now states that the amount on line 63d should equal the sum of all amounts reported in box 11 of all Forms 1042-S sent to recipients.
Check out the DRAFT 2021 Instructions for Form 1042 here: