Family Pension deduction under 57(iia) in new regime

Yes.

Under the new tax regime, for Financial Year 2025-26, a family pensioner can claim a standard deduction of ₹25,000 from their family pension income. This deduction was increased from the previous limit of ₹15,000, as announced in Budget 2025

Sir that means this is not applicable for FY 24-25 and only for FY 25-26 ?

Yes, that is true.     From FY 2025-26 onwards....           

1/3 OF Pension received or ( Rs.15000 in case of old regime,Rs.25000 in case of Default/new regime.) Which ever is less is applicable from FY 2024-25.