openrtb.3.0.version_header

What it means

OpenRTB 3.0 introduced header.x-openrtb-version, which openRTB 3.0 retained explicit version headers as part of the transport layer..

Why it matters

header.x-openrtb-version is only defined from 3.0 onward. Used against an earlier version it is not valid, and a consumer below 3.0 treats it as an unknown field.

How to fix it

Target OpenRTB 3.0 or later when you send header.x-openrtb-version, and make sure the value matches the type and any enum the specification defines for it.

Paste your bid request into the tester and select OpenRTB 3.0 to see whether this rule fires against your payload.

Reference

• Specification section: Layer-1: Transport / Version Headers
• Source: OpenRTB 3.0 final specification

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