IAB TCF v2.3: What Publishers Need to Know
Clickio Consent is fully updated to support TCF v2.3, with all changes now live across our CMP network.
The IAB Europe released Transparency and Consent Framework version 2.3 on June 19, 2025, with mandatory compliance required by February 28, 2026. This update introduces a critical technical change that affects how consent signals are generated and validated across the digital advertising ecosystem.
In this article, we break down what’s changed, why it matters, and what publishers need to do to stay compliant.
What is TCF v2.3?
TCF v2.3 is the latest iteration of IAB Europe’s industry-standard framework for managing user consent under GDPR. While TCF v2.2 focused on policy changes – most notably removing legitimate interest as a legal basis for personalized advertising – TCF v2.3 focuses on proof and verification.
The core innovation is making the Disclosed Vendors segment mandatory in all TC Strings. This provides a verifiable signal confirming which vendors were actually displayed to users during the consent collection process.
The Key Change: Mandatory Disclosed Vendors Segment
The Problem TCF v2.3 Solves
Under TCF v2.2, a significant ambiguity existed. When a vendor received a “0” signal for Legitimate Interest processing, they couldn’t distinguish between two scenarios:
- The user saw the vendor listed and actively objected
- The vendor was never shown to the user at all
This “ghost vendor” problem was particularly problematic for vendors relying on Legitimate Interest for Special Purposes like fraud prevention and security, where GDPR requires transparency regardless of consent status.
The Solution
TCF v2.3 resolves this by making the disclosedVendors segment mandatory in every TC String. This creates a binary bitfield where:
- Bit value “1” = vendor was displayed in the CMP user interface
- Bit value “0” = vendor was NOT disclosed to the user
This provides mathematical proof of disclosure, eliminating the signaling ambiguity vendors faced under v2.2.
TCF v2.2 vs TCF v2.3: Key Differences
| Aspect | TCF v2.2 | TCF v2.3 |
|---|---|---|
| Disclosed Vendors Segment | Optional | Mandatory |
| Vendor Disclosure Verification | Not verifiable | Binary proof |
| Primary Focus | Policy changes | Technical verification |
| “Ghost Vendor” Problem | Present | Resolved |
Timeline and Deadlines
Publishers should be aware of these critical dates:
| Date | Event |
|---|---|
| June 19, 2025 | TCF v2.3 officially released |
| November 2025 | Google confirms systems can accept and process TCF v2.3 strings |
| February 28, 2026 | Mandatory compliance deadline |
What Happens After February 28, 2026?
- TC Strings created without the
disclosedVendorssegment will be deemed invalid - Legacy strings created before March 1, 2026 remain valid until users renew or change their choices
What Publishers Need to Do
For Clickio Consent Users
No action required. Clickio Consent has been fully updated to support TCF v2.3, and all changes are live across our CMP network. Your consent strings are already being generated with the mandatory Disclosed Vendors segment.
Existing consents remain valid during the transition, and there’s no need to re-surface consent banners for this change.
For Publishers Using Other CMPs
Contact your CMP provider to confirm their TCF v2.3 timeline and readiness. You should also verify they maintain Google certification for TCF v2.3 compliance.
Consequences of Non-Compliance
Failure to comply by February 28, 2026 carries severe consequences. TC Strings without the disclosedVendors segment will be deemed invalid. This can result in significant programmatic revenue losses and reduced bids from major demand sources.
Conclusion
TCF v2.3 represents an important step forward in consent verification, providing record that vendors receiving consent signals were actually disclosed to users. While the change is primarily technical, the implications for compliance and revenue are significant.
The good news is that publishers using Clickio Consent don’t need to take any action – our platform is already fully compliant with TCF v2.3, and all changes are live across our network.
For publishers using other solutions, the February 28, 2026 deadline provides ample time to ensure compliance, but we recommend verifying your CMP’s readiness sooner rather than later to avoid any disruption to your programmatic revenue.
Clickio Consent is a Consent Management Platform certified by IAB Europe and Google, ensuring seamless global compliance.
Have questions about TCF v2.3 compliance? Contact us to learn more, or sign up for Clickio Consent to get started with a fully compliant CMP today.