# IAB TCF 2.3

**Overview**

The IAB Europe Transparency and Consent Framework (TCF) 2.3 introduces changes that impact how CMPs (Consent Management Platforms) handle **TC Strings** — particularly with the addition of a new **disclosedVendors** segment.

This article explains how Didomi’s CMP and SDK handle these updates, including requirements during the transition period and the creation and validation of TC Strings.

**Transition Period Handling**

To ensure compatibility between TCF 2.2 and 2.3, CMPs must handle TC Strings differently depending on when they were created:

* **Before February 28th, 2026:** We will continue to accept and process TC Strings that do not include the **disclosedVendors** segment. These strings remain valid.
* **After February 28th, 2026:** All new TC String will be generated with the disclosedVendors. Strings generated before this date remain valid.

This ensures a smooth transition to TCF 2.3 while maintaining backward compatibility during the transition period.

**Disclosed Vendors Segment Compliance**

Didomi’s SDK ensures that **all vendors surfaced to the user** are also included in the **disclosedVendors** segment when it is present in a TC String.

This guarantees alignment between what is shown in the user interface and what is recorded in the consent signal.

**Vendors with Special Purposes Only**

For vendors registered **only for Special Purposes**, the Didomi SDK continues to:

* Set the **Legitimate Interest (LI)** bit to **1**
* Include these vendors in the CMP disclosure

This behavior remains **unchanged** from previous TCF versions and is still required under TCF 2.3.

**User Interface and Resurfacing**

You are **not required** to resurface the consent UI as part of this update.

Existing user choices remain valid, provided the TC String complies with the handling rules above.

#### Side-by-side comparison of TCF v2.2 vs v2.3

![Didomi - TCF v2.2 vs v2.3 table](https://support.didomi.io/hubfs/Didomi%20-%20TCF%20v2.2%20vs%20v2.3%20table.avif)

 


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