2.2.6 [W3C-EPUB3] Section 4.4.1.2.2. Allowed values

C0009: The rendition:flow property is not supported

The specification states:

 › 4.4.1.2.2 Allowed values
  
 The following values are defined for use with the rendition:flow property:

EdgeHTML Mode

The rendition:flow property is not supported; instead, a default automatic flow mode is used.