Rajarshi Bardhan wrote:

Latest PDF version is 1.7.

At present, future PDF versions are it is looked after by ISO and not Adobe. Since ISO 32000 is equivalent to Adobe's PDF 1.7, Adobe is not producing a PDF 1.8 Reference. ISO will produce future versions of the PDF Specification. However, Adobe is publishing a document specifying what extended features for PDF, beyond ISO 32000-1 (PDF 1.7), are supported in its newly released products. This makes use of the extensibility features of PDF as documented in ISO 32000 in Annex E. Note that PDF documents conforming to ISO 32000 carry the PDF version number 1.7. Documents containing extended features still carry the PDF base version numer 1.7.

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