Can I adjust revenue in a closed accounting period?

No. You can adjust revenue for transactions in accounting periods that are in either Open or Close Pending statuses.

If you change the status of a closed accounting period to Open or Close Pending, you can adjust revenue for a transaction in that accounting period. Any adjustments to previously existing transactions and all new transactions (including manual events set to be reversed in the next accounting period) will be processed in the oldest Open or Close Pending accounting period following the accounting period in which the transaction date occurs, if that accounting period is closed.