One of the major reasons to migrate to PD4ML v4 API is the support of the PDF/UA standard (Universal Accessibility).

PDF/UA standard is to let people with disabilities access PDF information in an efficient manner without assistance from others and be able to receive the same value from the content as others. PDF/UA does not add any new features to the PDF file format, but makes some aspects required which are optional in a regular PDF.

A lot of the requirements, like fonts embedding, were implicitly fulfilled even by older versions of PD4ML. But the major ones are covered only starting from PD4ML v4 – thanks to the new product architecture, which has been designed bearing in mind PDF/UA conformance.