With the latest beta, PDF/A fails validation in a new way.

Using the example document in the wiki, PDF/A-1a validation fails the online validator [2] with:

The key MarkInfo is required but missing.
The key StructTreeRoot is required but missing.
The key CIDSet is required but missing.
The document does not conform to the requested standard.
The document contains fonts without embedded font programs or encoding information (CMAPs).
The document doesn't provide appropriate logical structure information.
The document does not conform to the PDF/A-1a standard.

while with PDF/A-1b requested, the MarkInfo and StructTreeRoot issues are not reported. (A-2a and A-3a fail in the same was as A-1a.)

[1] https://wiki.contextgarden.net/PDF/A

[2] https://www.pdf-online.com/osa/validate.aspx

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Rik