How to register Odoo as your CAS or CBA with the BIR: steps, documents and what comes after

"Is Odoo BIR-registered?" is one of the first questions we hear in the Philippines. The BIR does not register software brands. It registers your use of a system, at your RDO. So the real question is how your business registers Odoo. (If you would rather have Odoo set up with you, see our BIR CAS set-up service. You file the registration yourself.) This guide walks through the process as it stands in October 2026.

CAS or CBA?

RMO 9-2021 says registration applies to any software that records sales, purchases, receivables, payables, inventory or payroll, or that produces BIR reports. It also covers cloud (hosted) systems and third-party providers, so a cloud set-up such as Odoo Online or Odoo.sh is registered too, with the joint sworn statement described below.

How registration works now

• No Permit to Use. RMC 5-2021 replaced the PTU with registration, and RMO 9-2021 repealed the old rules (RMO 29-2002).
• Acknowledgement Certificate in three working days. The RDO issues the AC once your documents are complete. It carries an AC control number (ACCN), which your system-generated invoices show.
• Post-evaluation. There is no demonstration before you start. The RDO evaluates the system afterwards against the BIR's functional and technical requirements, and can revoke the AC if it finds gaps.
• Where to file. At your RDO or Large Taxpayers office, in person or by email. Sister companies and affiliates register separately, even on a shared system.
• Cloud or third-party systems. You and the provider sign a joint sworn statement that the system cannot suppress sales. If the provider contract ends, the registration is cancelled.

What goes in the application

The checklist in RMC 5-2021 Annex A asks for:

1. A sworn statement (or joint sworn statement for an outsourced or cloud system), with a system description, a description of your invoices and documents, and the list of forms, records and reports.
2. Sample printouts of your invoices and supplementary documents.
3. Sample printouts of your books of accounts and other system reports.
4. A printed audit trail from the system.
5. The signed checklist of functional and technical requirements (Annex B).

Annex labels differ between RMO 9-2021 and RMC 5-2021, so ask your RDO for its current templates.

What the system must do

Annex B of RMC 5-2021 sets the requirements. The ones that matter most:

• An audit trail of all activity that can be printed, protected from change.
• Posted transactions can be voided, not modified, and the system controls the numbering.
• Every record stamped with the user who created it, and reports with the date, time and user.
• Invoice serial numbers generated by the system, with at least six running digits, and "REPRINT" on copies.
• Report headers with your registered name, address, TIN with branch code, and the software name and version.
• Exports of books and reports in CSV or DAT, and the ability to produce the 2306, 2307 and 2316.
• Security: unique user IDs, password rules, lockouts and logged database changes.
• Backups kept for ten years.

Odoo already has the building blocks: an audit trail that logs changes to accounting records, posted entries secured with a hash chain, irreversible hard lock dates, and the Philippine localisation's BIR reports. Odoo 20's release notes add a Book of Accounts for CBA and CAS and update Philippine invoices for BIR and CAS requirements. Whether your set-up meets every Annex B item depends on configuration and hosting. We review the set-up with you before you apply; the RDO makes the evaluation.

Changes and upgrades

• Major enhancements need an updated registration before you use them. That includes adding or removing financial modules, or a version change that affects the financial side. If you skip it, the registration has no effect from the date you adopt the change.
• Minor enhancements need a written notice: screen changes, bug fixes, performance improvements.
• RR 11-2024 treated the EOPT invoicing changes to a registered CAS or CBA as a major enhancement, with an updated registration and a new AC.
• An Odoo major-version upgrade that changes accounting features is likely to count as a major enhancement. Plan the update with your RDO alongside the upgrade itself.

Every year: register your books in ORUS

Under RMC 3-2023 and RMC 4-2026, computerised books are registered online through ORUS, which issues a QR code you print and keep. For taxable year 2025, the deadline for computerised books was extended to 17 February 2026. Earlier rules also asked for the books on a USB drive with a transmittal letter, so check with your RDO what it wants with the ORUS registration.

E-invoicing adds a second permit

RMC 98-2026 is clear that the AC authorises the use of your system but not the issue of e-invoices. If you are covered, you also need:

• a Permit to Issue (PTI) e-invoices, decided within 20 working days of a complete application;
• EIS Certification within six months of the PTI;
• a new or amended PTI if you migrate to another invoicing system.

The covered groups and the 31 December 2026 deadline are in our BIR e-invoicing guide.

A realistic order of work

1. Set up Odoo with the Philippine localisation, audit trail, secured journals and your invoice layout.
2. Produce the samples: invoices, books, reports and the audit trail printout.
3. File for the AC at your RDO and keep the ACCN for your invoices.
4. Apply for the PTI if you are covered by e-invoicing, using your RDO's current documentary requirements.
5. Register your books in ORUS each year.

You don't need to hire your own team. A TechNext adviser maps your registration path first, then our team in Taguig City sets up Odoo and prepares the system samples with you for the application you file. See how we set Odoo up as your CAS.

Sources

• RMO 9-2021 and RMC 5-2021 (copies hosted by Grant Thornton)
• RMC 5-2021 Annex A: checklist and Annex B: functional and technical requirements (BIR)
• RMC 4-2026 and RR 11-2024 (BIR)
• Grant Thornton: online registration of books via ORUS
• RMC 98-2026 (copy hosted by KPMG) and the circular itself (BIR)
• Odoo 20 release notes and Odoo documentation: data inalterability and year-end closing and lock dates

Common questions