Your BIR Computerized Accounting System, set up in Odoo for you to register

A Computerized Accounting System (CAS) is the system your business registers with the BIR to issue invoices and keep its books. We set Odoo up for your CAS or CBA application, prepare with you the samples your Revenue District Office asks for, and stay on for the yearly books and e-invoicing planning. You register at your RDO; the decision is the BIR's.

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CAS or CBA, head office and branches
Samples taken from your own Odoo
Odoo Ready Partner

What you register: Your use of a system, at your RDO, not a software brand
What you receive: An Acknowledgement Certificate (AC) with an AC control number
How long: Per RMC 5-2021, three working days after a complete application; the RDO decides
Every year: Computerised books registered online in ORUS

A Computerized Accounting System (CAS) records your transactions, generates your invoices and produces your books of accounts and BIR reports. Large taxpayers must use one; other businesses may choose a CAS or Computerized Books of Accounts (CBA). Since RMC 5-2021 there is no Permit to Use: your Revenue District Office (RDO) issues an Acknowledgement Certificate within three working days of a complete application and evaluates the system afterwards. You register your system at your RDO. We set Odoo up and prepare the sample printouts and audit trail with you; the decision is the BIR's. We also plan the yearly ORUS books and, if you are covered, the Permit to Issue you apply for.

BIR notice: no software is BIR-accredited

The BIR registers your business's use of a system; it does not approve software brands. In a public advisory dated 14 September 2026 it said it has not accredited, certified or endorsed any e-invoicing service provider, and warned against claims such as "BIR-accredited". RMC 110-2026 (12 October 2026) sets the accreditation rules for e-invoicing service providers; no list had been published when we wrote this. We set Odoo up for BIR requirements and prepare your samples with you. The registration decision is the BIR's. TechNext is an Odoo Ready Partner. We are not affiliated with, accredited by or acting for the BIR or any government agency, and we do not file or register on your behalf.

CAS or CBA: which one you register.

RMO 9-2021 draws the line at invoices. If your system issues them, it is a CAS.

Compared	CAS (Computerized Accounting System)	CBA (Computerized Books of Accounts)
What it covers	The full cycle, from the transaction and the invoice to the financial reports	Books of accounts only: journals, ledger, sales and purchase books, inventory book
Invoices	System-generated	Issued manually (a system that issues invoices by hand counts as a CBA)
Who must use it	Large taxpayers must maintain or use a CAS (RR 9-2009, restated in RMO 9-2021)	Optional for non-large taxpayers, who may choose a CAS or a CBA
Cloud set-ups	Registered too. Odoo Online or Odoo.sh needs a joint sworn statement with the provider that the system cannot suppress sales.

What the BIR checks in your system, and what Odoo already has.

Annex B of RMC 5-2021 lists the functional and technical requirements. The RDO evaluates them after it issues your certificate, so check them before you file.

In Odoo 20

An audit trail that logs changes to accounting records
Posted entries secured with a hash chain, and irreversible hard lock dates
A Book of Accounts for CAS and CBA, and Philippine invoices updated for BIR and CAS requirements
The Philippine localisation's reports: 2307, SLSP, SAWT, QAP and the 2550Q summary

What TechNext sets up

Every Annex B item checked against your configuration and hosting
Invoice layout and series: six running digits, your AC control number, "REPRINT" on copies
User roles, password rules and report headers with TIN, branch code and software version
A backup plan that keeps your records for ten years

Sources: RMC 5-2021 Annex B, the Odoo 20 release notes and Odoo's documentation on data inalterability. Whether a set-up meets every item depends on its configuration and hosting, which we review with you before you apply; the RDO makes the evaluation.

What goes in your CAS application.

The checklist in RMC 5-2021 Annex A. Every sample comes from the Odoo you will actually use, so what the RDO sees is what you run.

Read the full CAS and CBA guide

1
A sworn statement
Or a joint sworn statement for a cloud or outsourced system, with a description of the system, your invoices and the forms, records and reports it produces.
2
Sample invoices
Printouts of your invoices and supplementary documents, as Odoo generates them.
3
Sample books and reports
Your books of accounts and the other system reports, printed from Odoo.
4
An audit trail printout
Printed from the system, showing who did what and when.
5
The signed requirements checklist
The functional and technical requirements in Annex B. Ask your RDO for its current templates, as annex labels differ between issuances.

From "which do we need?" to your CAS application.

You don't need to hire your own team. An adviser maps your registration path first, then our team in Taguig City sets up Odoo and stays on after go-live.

1Map your registration path
CAS or CBA, head office and branches, any old Permit to Use, and with your accountant, whether e-invoicing applies to you now.
2Set up Odoo
Philippine localisation, audit trail, secured journals, lock dates, user roles, invoice layout and series.
3Prepare the samples
Invoices, books, reports and the audit trail printout, taken straight from your Odoo.
4You file at your RDO
In person or by email. We stay on call for the RDO's questions, and your invoices carry the AC control number.
5ORUS every year
You register your computerised books online through ORUS and keep the QR code on file; we prepare the book exports from Odoo.
6E-invoicing and upgrades
If you are covered, you apply for your Permit to Issue and EIS Certification; we prepare the Odoo outputs and assess the EIS connection separately. Major upgrades are planned so you can file the updated registration first.

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Already registered? When your CAS needs updating.

Changes to a registered system have their own rules. These are the ones we plan around.

Odoo 20 upgrade checklist

Major enhancements
Adding or removing financial modules, or a version change that affects the financial side, needs an updated registration before you use it. Skip it and the registration has no effect from the date you adopt the change.
Minor enhancements
Screen changes, bug fixes and performance improvements need only a written notice.
EOPT invoice changes
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 Acknowledgement Certificate.
An old Permit to Use
A PTU stays valid unless it is revoked or the system has a major enhancement.
Sister companies and branches
Affiliates register separately, even on a shared system. Read BIR set-up for multi-branch businesses.

BIR CAS registration, answered.

The questions Philippine finance teams ask us before an Odoo project.

What is a BIR Computerized Accounting System (CAS)?

A CAS is a computerised system that records a business's transactions, generates its invoices and produces its books of accounts and financial reports. Under RMO 9-2021 a business registers its CAS with the BIR at its Revenue District Office (RDO) or Large Taxpayers office. If the system issues invoices by hand, it counts as Computerized Books of Accounts (CBA) instead.

Is there BIR-accredited accounting software?

No. The BIR registers each taxpayer's use of a system, not a software brand. In its public advisory of 14 September 2026 it said it has not accredited any e-invoicing service provider and warned against "BIR-accredited" claims. Your business registers Odoo as its CAS or CBA and, if the RDO accepts the application, receives an Acknowledgement Certificate. See BIR rules for your accounting system.

Do I still need a Permit to Use (PTU)?

No. RMC 5-2021 replaced the Permit to Use with registration and an Acknowledgement Certificate (AC). Existing PTUs stay valid unless revoked or the system has a major enhancement.

How long does CAS registration take?

Under RMC 5-2021, the RDO issues the Acknowledgement Certificate within three working days of a complete application; the timing and the decision are the RDO's. There is no demonstration before you start: the RDO evaluates the system afterwards and can revoke the certificate if it finds gaps, which is why we review the requirements with you before you file.

Can Odoo Online or Odoo.sh be registered as a CAS?

Yes. RMO 9-2021 covers cloud and third-party systems. You and the provider sign a joint sworn statement that the system cannot suppress sales, and the registration is cancelled if the provider contract ends.

Does my Acknowledgement Certificate let me issue e-invoices?

No. Under RMC 98-2026 the AC authorises the system but not e-invoicing. Covered taxpayers also need a Permit to Issue (PTI), then EIS Certification within six months, and the covered groups must issue e-invoices by 31 December 2026.

Do I need to re-register after upgrading Odoo?

A version change that affects the financial side counts as a major enhancement, which needs an updated registration before you use it. Minor changes, such as screen changes or bug fixes, need only a written notice. We plan the upgrade so you can file the updated registration first.

Does TechNext file the CAS application for us?

Your business files at its RDO or Large Taxpayers office, in person or by email. We set up the system, prepare the sample printouts, the audit trail and the system description with you, and stay on call for the RDO's questions. The registration decision is the BIR's.

BIR guides from our advisers.

Each one names its sources and the date it was checked.

Sources

Updated 22 October 2026

Registration is done by each taxpayer at its own RDO; TechNext prepares the system and samples, not the BIR's decision. General guidance, not tax advice. Rules change: confirm with your accountant or RDO before you act.

Planning to register Odoo as your CAS?

Tell us how you invoice and keep your books today. An adviser will say whether you need a CAS or a CBA, what Odoo covers, and what it takes to file.