Please note the following correction.
On page 11 of the 2021 version of Publication 501, the text under ※Adopted child§ has been corrected to read:
※You may be eligible to file as a qualifying widow(er) if the child who qualifies you for this filing status you adopted in 2021 or was lawfully placed with you for legal adoption by you in 2021. The child is considered to have lived with you for all of 2021 if your main home was this child＊s main home for the entire time since he or she was adopted or placed with you in 2021.§
We removed references to foster child from the paragraph.
The corrected version will be available for download soon.