Acknowledgment No. and date to be mentioned in revised Income tax return

When you change your tax return, it replaces the old one. If you change it again, you need to mention the last change. Only the most recent version counts, and all updates link back to that.

Thanks, but can you please share some reference link or material as I would like to check the source?

As per Section 139(5) of the Income-tax Act, each revised return substitutes and supersedes the return filed earlier. Therefore, when filing a second revised return, the acknowledgement number and date of filing of the immediately preceding revised return should be mentioned, and not that of the original return. The latest revised return becomes the operative and valid return on record, and the income-tax portal also links the subsequent revision to the most recent return filed.Accordingly, in case of multiple revisions, reference should always be made to the latest revised return.

If you're still unsure, please wait. I'll ask Sir and get back to you tomorrow.