What is the Child Tax Credit Update Portal (CTC UP)?
The CTC Update Portal (CTC UP) allowed families to update relevant information about their Child Tax Credit (CTC) payments. Last year, CTC UP allowed users to opt out of advance CTC payments, change payment information, and check overall eligibility status. Because monthly payments have stopped this year, you shouldn't have to use the CTC Update Portal. You should file a tax return to claim the rest of this year's CTC.
If you need to see the amount of advance payments you received last year, you can go to your online IRS account.