schemaVersion

Канонический URL: http://schema.org/schemaVersion
Indicates (by URL or string) a particular version of a schema used in some CreativeWork. For example, a document could declare a schemaVersion using an URL such as http://schema.org/version/2.0/ if precise indication of schema version was required by some application.
Ожидаемые значения должны быть одного из этих типов
URL
Text
Используется в таких типах
CreativeWork

Schema Version 3.3