VAST-2.0-root-version-value
VAST version attribute must be a recognised version string
Short answer
The version attribute value must be one of the officially released VAST versions: 2.0, 2.0.1, 3.0, 4.0, 4.1, 4.2, or 4.3. An unrecognised value usually means a typo — for example 4 instead of 4.0.
Why this matters in production
This rule is a strong risk signal. Tags with this issue often still parse, but they become brittle across SDKs, SSAI resolvers, and CTV environments. Required-field failures usually stop validation early because the platform cannot determine the basic shape of the ad, the creative metadata, or the mandatory tracking payload. Affected scope: VAST 2.0 and later (all versions).
How to fix
Change the version attribute to a recognised value: 2.0, 2.0.1, 3.0, 4.0, 4.1, 4.2, or 4.3.
Invalid
<VAST version="4">Valid
<VAST version="4.0">VAST-2.0-root-version-value and other issues instantly.Validate a tag →