One more piece in the IBS/CBS puzzle: version 1.51 of NT 2025.002-RTC
Anyone following the implementation of the Tax Reform in electronic tax documents has already noticed the pattern: Technical Note 2025.002-RTC has not received a single update, but rather a sequence of versions that adjusts fields, groups, and validation rules for NF-e and NFC-e throughout 2025 and 2026. The most recent version, 1.51, was published on August 1, 2026, and brings an important message for tax and IT teams: part of the schedule has been relaxed, but another part remains firm — and it is necessary to know how to tell one from the other.
What changes with v1.51
Version 1.51, published on August 1, adjusted the implementation deadlines for some validation rules to reflect the relaxations provided for in Joint Technical Act RFB/CGIBS No. 1/2026. Two points deserve immediate attention from tax and IT teams:
Version 1.51 changed the schedule for stage 3 of the Technical Note, extending the deadline for implementation in the test environment of the validation rules to September 1, 2026. Meanwhile, the referencing of documents in return processes, handled by the DFeReferenciado group, received its own adjustment: validation rule VC02-14 will be implemented in the production environment on October 5, 2026, a relevant change for those who had already been preparing for September 1 on this specific point.
An important operational alert: not every rule was pushed back. Rule UB12-10 follows the originally set schedule, with implementation scheduled for August 3, 2026, and is not covered by the extension granted by version 1.51. In other words, anyone who configured their system assuming everything was postponed runs the risk of seeing invoices rejected by this specific rule, which is already in effect.
The industry highlight: single-phase fuel taxation
The most structural change, however, came a bit earlier, in version 1.50, and was kept in 1.51. The Brazilian Federal Revenue Service, together with the IBS Management Committee and Encat, published, on June 2, 2026, Technical Note 2025.002-RTC – Version 1.50, with the redesign of the layout for single-phase fuel taxation, accompanied by the creation and update of fields, adjustments to validation rules, and improvements to controls related to IBS, CBS, and the Selective Tax.
In practice, this means a deep restructuring of Group UB (IBS, CBS, and IS information) for companies that resell or distribute fuel. A group was created to control differences related to the mandatory blending of anhydrous fuel ethanol (EAC) into gasoline, along with a specific group for CBS Monofásica Ad Rem and a group for standard single-phase taxation information. The calculation methods were also differentiated: fields were created to distinguish the application of ad rem rates (a fixed amount per unit) and ad valorem rates (a percentage of the value), with specific transition rules for each tax.
Schedule that stood firm
Despite the adjustments brought by v1.51, the specific timeline for single-phase fuel taxation did not change. The changes introduced by NT 2025.002 v1.50 will follow the official schedule: test environment on September 1, 2026, and production environment on November 3, 2026. It is worth remembering that availability in the test environment may occur on different dates across the different States, according to each tax administration's own schedule, which reinforces the importance of monitoring state-level announcements in addition to the federal calendar.
What to review by September
- NF-e/NFC-e issuing systems used by fuel distributors, resellers, and gas stations need to validate the new restructured Group UB before the September 1 test environment deadline.
- Companies that handle merchandise returns should internally reschedule their target to the new October 5 date (VC02-14), without abandoning the tests already underway.
- Rule UB12-10, already in effect since August 3, should be treated as a current priority, not a future item.
- IT and tax teams should review the cClassTrib configuration tool, since the completion of the new fuel groups is tied to this code.
This is one more chapter in a process that continues in monthly waves through 2027. Keeping the ERP updated with these technical notes, along with a close monitoring channel with the accounting team, is what prevents batch rejections and last-minute rework.
This content is for informational purposes only and does not replace guidance from an accountant or a qualified tax professional for your company's specific situation.
Want to understand how this impacts your company's tax operations within Odoo? Talk to Edoo and assess your configuration before the September window.
NT 2025.002-RTC v1.51: the new deadline roadmap for the Tax Reform in NF-e and NFC-e (with a focus on single-phase fuel taxation)