PDF/A-4 was published in the fall of 2020 and is therefore the latest part of the PDF/A series of standards. It is based on ISO 32000-2 (PDF 2.0) and is both an evolution of PDF/A-3, which is based on ISO 32000-2 (PDF1.7), and a consolidation of the PDF/E standard.
The -a ("Accessibility"), -u ("Unicode") and -b ("Basic") conformance levels that we know from earlier PDF/A variants are no longer offered in PDF/A-4. Instead, the standard comes with two new profiles:
PDF/A-4e: PDF/A-4e ("Engineering") is intended for technical documents and replaces PDF/E. PDF/A-4e supports 3D models, rich media and 3D annotations as well as embedded files.
PDF/A-4f: The requirements of PDF/A-3 have also been partially incorporated into PDF/A-4. Thus PDF/A-4f allows the embedding of arbitrary files.
PDF/A-3 vs PDF/A-4
Since PDF 2.0, on which PDF/A-4 is based, is not yet established, it will probably be some time before PDF/A-4 becomes widespread on the market. This is because PDF/A-4 must not only be able to be created, but also validated and processed. However, many processing lines are not equipped for this. For the time being, we only advise customers to use PDF/A-4 if they have specific needs, such as archiving engineering documents.