What happens if people miss December 31 deadline to file revised ITR?

The last date to file a revised ITR for AY 2025-26 is December 31. The refund might get delayed if one misses the deadline, especially for those who have errors and missing details that lead to incorrect refund claims, said NDTVProfit. Also, Income Tax Department could do a detailed investigation on the case if people don't file a revised ITR.