Every second question this filing season is some version of the same worry: "There's a new Income-tax Act — do I have to relearn everything before I file?"
The short answer is no. The return you are filing now is still under the old Act. Here is why, and what actually does change.
The rule in one line
The year you earned the income decides the law — not the date you file.
That single sentence resolves almost all of the confusion. Filing in July 2026 does not put you under the 2025 Act, because the income you are reporting was earned in FY 2025-26 — before the new Act commenced.
The year-wise table
| Income earned in | Old name | Governing law | When you file |
|---|---|---|---|
| FY 2024-25 and earlier | AY 2025-26 and earlier | 1961 Act (including pending notices, assessments, appeals) | Already filed / belated |
| FY 2025-26 | AY 2026-27 | 1961 Act — even though you file after 1 April 2026 | This season |
| From 1 April 2026 | Tax Year 2026-27 | 2025 Act | In 2027 |
So for this year's return: old Act, old section numbers, old ITR forms, familiar process. Nothing about your filing changes because of the new Act.
Why old-year notices still quote old sections
The 2025 Act contains savings provisions that create a clean dual track: every notice, assessment, appeal or proceeding relating to a period before April 2026 continues under the 1961 Act, with its original numbering.
This matters practically. If you receive a notice quoting Section 148 (reassessment) or Section 143(2) (scrutiny) for an earlier year, that is correct and current — not a stale template. Replies to those should cite the old sections too. If you're unsure how to read one, see our page on tax notices and assessments.
What the new Act does change — and when
The 2025 Act is a re-codification, not a policy change. It says the same things in cleaner language, with tables and formulas replacing nested provisos. What it changes is where things live:
- Section numbers move. 80C becomes s.123, the new regime moves from 115BAC to s.202, the rebate from 87A to s.156, tax audit from 44AB to s.63. Nothing is withdrawn — the same reliefs sit at new addresses. Our old-to-new mapping quick reference has the table.
- "Tax Year" replaces "Previous Year" and "Assessment Year." One term instead of two.
- From April 2026 onwards, your TDS certificates, investment-proof declarations and any new-year notices will progressively carry the new numbers.
None of that touches the return in front of you now.
What you should actually do
- Filing this year (FY 2025-26): proceed entirely under the 1961 Act. Old sections, old forms, familiar process.
- Don't panic at new numbers from April 2026 onwards. When 80C appears as 123 on a declaration, it is the same deduction.
- If you have pending notices or appeals for old years: they continue under the 1961 Act — reply citing old sections.
- Keep the due dates straight. For AY 2026-27 the deadline depends on your category, not one common date — see the ITR filing page for the tiered dates.
The new Act is a genuine simplification, and it is worth understanding — but it is next year's problem for your return, not this year's. For the complete picture of what changed and what didn't, read the full comparison of the 2025 and 1961 Acts.