How do I check which OpenRTB version a partner is running?

Answer

Look at the x-openrtb-version HTTP header on their requests; the spec has exchanges declare the version there (for example x-openrtb-version: 2.6). Beyond the header, the payload itself tells you: regs.gpp means at least the 2.6-202211 snapshot, plcmt on video means 2.6-202303 or later, and gdpr still living at regs.ext.gdpr suggests a 2.5-era integration regardless of what the docs claim. Partner documentation lags reality often enough that fingerprinting the actual traffic is the reliable method.

Fields in this answer

FieldTypeSinceStatus in 2.6
regs.gppstring2.6-202211Current

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