Missed the ITR filing deadline Don't worry, there is still a chance. The ITR-U lets you fix errors or report income you forgot. File within four years, but remember there is an extra tax. Some changes are not allowed, like claiming more refund. ITR-U offers a way to correct mistakes, but know the rules and costs.
source https://timesofindia.indiatimes.com/business/financial-literacy/taxation/itr-filing-what-is-updated-income-tax-return-and-itr-u-who-can-file-what-you-cant-change-top-points-to-know/articleshow/123392095.cms
source https://timesofindia.indiatimes.com/business/financial-literacy/taxation/itr-filing-what-is-updated-income-tax-return-and-itr-u-who-can-file-what-you-cant-change-top-points-to-know/articleshow/123392095.cms