OIR 26.1: Release Notes and Announcement

What changed in 26.1?

The release notes describe more than 900 formatting, terminology, metadata, and classification corrections across the digital environment. The purpose is to improve information quality, navigation, and interoperability. Those corrections do not represent revisions to approved CSI standard editions. The release also reflects an initial UniFormat® expansion framework under development through CSI's established standards process.

The platform changelog identifies six visible areas of change: Standard, Edition, and OIR selectors; a divisions view; a Changes in 26.1 page; broader Document Transition Tool support; signup and user-management updates; and reorganized crosswalk groups. Some changes affect the way a user navigates. Others improve the information that search and relationships depend upon.

Select the standard, edition, and operational release separately

CSI Dynamic Standards and Division Hierarchies now present three dropdowns. Start with the classification system appropriate to your task, check the edition, and then choose the OIR. MasterFormat® 2026 Edition remains distinct from OIR 26.0 and OIR 26.1; the OIR identifies the operational information state. Keeping these selections distinct helps teams explain what they reviewed without treating the decimal release number as a new edition title.

For a specification reference, start with the MasterFormat 2026 Edition · OIR 26.1 guide. For early planning and element-based classification, read the UniFormat 2010 Edition · OIR 26.1 guide. For lifecycle tables and related classifications, use the OmniClass® 2.2 · OIR 26.1 guide. Each guide addresses a different information task within the same release.

Review changes before updating project information

The paid Changes in OIR 26.1 tool helps users review current classifications and their predecessors across MasterFormat, OmniClass, and UniFormat when updating to OIR 26.1. Separately, the Document Transition Tool now supports moving from any MasterFormat OIR to 26.1. These are useful starting points for a controlled review of existing references. A team should still check its project context, contractual requirements, and dependent records before adopting a different classification reference.

Our transition guide explains a review sequence. The crosswalk guide explains how to interpret relationships between standards, and the navigator guide covers browsing the hierarchy. Use these guides together when a change touches both documents and connected data.

Who should review this release?

Specifiers can review existing work-result references, estimators can check element-to-work-result relationships, and BIM or asset teams can examine the context of related OmniClass information. Administrators should also be aware that signup and user management were updated to support OIR selection. The release is shared, but the checks that matter depend on the records a team actually maintains.

Release date, standards authority, and access

CIN published OIR 26.1 on September 22, 2026 for information delivered through CSI Dynamic Standards. An Operational Information Release updates the digital information environment. CSI continues to govern, develop, and approve the underlying standard editions through its established consensus process. An OIR number should therefore be recorded separately from the standard name and edition when documenting a project reference.

Use the full release notes for the published scope and the September 22 changelog for the platform changes. The announcement from Chris Anderson explains the release's purpose. These public guides provide orientation; verify individual classifications and relationships in the licensed environment before applying them to project documents. Existing customers can log in, and teams evaluating access can review CSI Dynamic Standards pricing.