The Transparency & Consent Framework (TCF) is an industry standard developed by IAB Europe to help publishers, advertising platforms, and CMPs (Consent Management Platforms) comply with the GDPR in collecting and transmitting user consent.
Version 2.3 introduces technical and transparency changes that will become mandatory from 28 February 2026.
What changes with TCF v2.3
Your banner must “demonstrate” which vendors it has shown to the user
Until now, when a user interacted with the consent banner, the generated string (TC string) recorded the user’s choices but did not clearly certify which vendors were actually shown in the banner.
With TCF v2.3, the TC string must include a new mandatory data point — the "Disclosed Vendors" segment — which works like an attendance list: for each vendor, it indicates with a simple yes/no whether it was shown to the user.
Why is this important?
Without this information, some vendors could not be certain whether the user had been informed of their presence. This created a grey area, especially for vendors processing data for technical purposes. TCF v2.3 eliminates this ambiguity.
What does NOT change
TCF v2.3 is an update that happens “behind the scenes”. For publishers using a commercial CMP
- The banner stays the same — there is no change to the appearance or the content shown to users.
- There is no need to collect consent again — choices already expressed by users remain valid.
- The rules on consent and legitimate interest do not change — these were already updated with TCF v2.2 in 2023.
In most cases, the CMP Provider will handle the technical update automatically.
How to check if you are up to date
Method 1: IAB TCF String Decoder (recommended)
Step 1 — Install the Chrome extension Consent Data Validator from the Chrome Web Store.
Step 2 — Browse your site in incognito mode.
Step 3 — Accept consent from the banner.
Step 4 — Open the extension and copy the value of the TC string (the field tcString).
Step 5 — Go to an IAB TCF String Decoder online and paste the TC string.
Step 6 — In the decoded output, look for the "Vendors Disclosed" section:
- If the section is present → You are compliant with TCF v2.3. You do not need to do anything.
- If the section is missing → Contact your CMP provider to request the update.
Important: check your vendors
In addition to updating the version, make sure that all advertising vendors used are included in your CMP.
Failure to include one or more partners may reduce access to programmatic demand and impact revenue.
Check the updated list of required vendors for HBAgency:
https://support.hbagency.ai/hc/en-gb/articles/15243959402397-List-of-Vendors-Required-for-HBAgency
If you have any doubts about your current configuration or need help, contact our support team at support@hbagency.ai.