With income tax rules constantly changing, it's crucial for practicing chartered accountants (CAs) to remember and adhere to compliance deadlines. The financial year 2025-26 (AY 2026-27) brings several major changes for professionals, including new tax audit thresholds and stricter UDIN generation rules. This detailed blog post will keep you updated with all the important rules, dates and new changes this year.

1. Important dates for tax audit and ITR filing

Below are the important deadlines for filing tax audit reports and income tax returns (ITR) this year:

• Tax Audit Report (Form 3CA/3CB + 3CD): Last date is 30th September 2026.
• ITR filing for audit cases: Last date is October 31, 2026.
• Form 3CEB (Transfer Pricing Audit Report): Last date is October 31, 2026.
• ITR filing for transfer pricing cases: Last date is November 30, 2026.

2. ICAI's new tax audit limit rule (effective April 1, 2026)

As per ICAI Notification No. 1-CA(7)/234/2025 (dated 25.07.2025), major changes have been made in the maximum limit for tax audit:

• Per-partner limit: Each CA partner can now sign a maximum of 60 tax audit assignments in a financial year. This limit applies per partner, not per firm.
• No Transfer of Limits: Pooling or transferring unused limits between partners is not allowed.
• Multiple Partnership: If a CA is a partner in more than one firm, the total number of audits signed by him (across all firms combined) should not exceed 60.
• Head Office and Branch: Head Office (HO) and Branch audit of the same company/entity will be considered as a single assignment only.
• Exclusions: Audits under presumptive taxation (Sections 44AD, 44ADA, and 44AE) will not count towards this 60 limit. Furthermore, revised tax audit reports are also excluded from this limit.

3. Due dates for filing TDS/TCS returns (FY 2025–26)

These dates are applicable for Form 24Q, 26Q, 27Q and 27EQ:

4. Advance Tax Schedule (FY 2026–27)

The advance tax instalments for the upcoming financial year are as follows:

• First installment (15% cumulative): June 15, 2026
• Second tranche (45% cumulative): September 15, 2026
• Third tranche (75% cumulative): December 15, 2026
• Fourth installment (100% cumulative): March 15, 2027

Note: Taxpayers opting for presumptive taxation under sections 44AD/44ADA can pay their entire advance tax liability in one go by March 15, 2027.

5. Date of issue of Form 16

• Form 16 (Salary TDS Certificate): Last date of issue is 15 June 2026.
• Form 16A (Non-Salary TDS Certificate): Mandatory to be issued within 15 days from the date of filing of TDS return.

6. ITR Filing Due Dates (FY 2025–26 | AY 2026–27)

• ITR-1 and ITR-2 (salaried/non-professional taxpayers): July 31, 2026
• ITR-3 and ITR-4 (Business/Profession – Non-Audit Cases): August 31, 2026 🆕 New
• Audit due: October 31, 2026
• Transfer pricing matters: November 30, 2026
• Belated Return u/s 139(4): December 31, 2026
• Revised Return u/s 139(5): 31 March 2027 🆕 New

7. Key and new changes for the financial year 2025-26

• ITR-3 and ITR-4 date extended: The last date for non-audit cases has been extended from July 31 to August 31.
• Revised Return Filing Extended: The deadline for filing Revised Return has been extended from December 31 to March 31.
• ITR-U (Updated Return): The window for filing updated returns has been extended from 2 years to 4 years.
• Tax Audit Limit: A maximum limit of 60 tax audits per partner has been imposed.

Important changes made in Form 3CD:

• Clause 22 (MSME dues): Classification of MSME dues (on or after 45 days) is now mandatory.
• Clause 21: Disclosure of legal settlement expenses is required.
• Clause 36B: New clause has been added for deemed dividend.
• Clauses 28 and 29: These clauses have been omitted completely.

8. UDIN Updates (effective April 1, 2026)

The UDIN portal will now operate completely on system-enforced rules:

• Auto-stop of 60 audits: Once a partner completes 60 tax audit assignments across different firms, the system will automatically block generation of new tax audit UDIN.
• Signature Date Main Basis: 60 Audit will be counted from the date of signing of the audit report and not from the date of generation of UDIN.
• Applicable sub-categories: Form 3CA (u/s 44AB), Form 3CB (u/s 44AB(a)), Form 3CB (u/s 44AB(b)), and Form 3CB (Combined) will fall under this limit.
• Excluded Sub-Categories: Clauses (c), (d), and (e) under Form 3CB are excluded from this limit.
• Revised Report: If any tax audit report is revised, it will not be counted again in this limit.
• Predecessor Auditor Details: Except for the first year audit, it is mandatory to provide the name, MRN, NOC status and outstanding fees details of the previous auditor.
• Auditor's Opinion: You must select your opinion (Unmodified/Qualified/Adverse/Disclaimer) while generating the UDIN. You must also report on KAM, EOM, Other Matter, and Going Concern in Yes/No.
• UDIN Revocation Window: Now, a UDIN can only be revoked within 48 hours of its generation. Changes will not be permitted after that.