The Standard
What is PDF/UA-2?
PDF/UA-2 (ISO 14289-2:2024) is the ISO standard for universally accessible PDF documents built on PDF 2.0 (ISO 32000-2:2020). Published in 2024, it is described by the PDF Association as the "gold standard" for accessibility in PDF 2.0.
PDF/UA-2 does not replace PDF/UA-1 (ISO 14289-1:2014). PDF/UA-1 remains the standard for accessible PDF 1.7 documents, while PDF/UA-2 covers PDF 2.0 documents. Both standards coexist — and we validate against both.
The standard was developed by ISO TC 171/SC 2, the same committee responsible for the PDF specification itself, and is available from ISO.
Comparison
PDF/UA-1 vs PDF/UA-2: what changed.
| Capability | PDF/UA-1 | PDF/UA-2 |
|---|---|---|
| PDF version | 1.7 (ISO 32000-1) | 2.0 (ISO 32000-2) |
| Structure element attributes | ||
| MathML support | ||
| Modern Unicode handling | ||
| Associated Files (AF) | ||
| Annotation requirements | ||
| Namespace support | ||
| Intra-document link rules |
PDF/UA-2 is a complete rewrite of the accessibility specification for PDF 2.0. Key additions include comprehensive requirements for structure element attributes, detailed rules for math content including native MathML support, modern Unicode handling for multilingual documents, and requirements for the Associated Files feature introduced in PDF 2.0.
Why It Matters
PDF/UA-2 handles documents PDF/UA-1 can't.
Math and STEM content
PDF/UA-2 introduces native MathML support. Equations and formulas can be represented in a way that screen readers and Braille displays can interpret, rather than being flattened to images with alt text.
Multilingual documents
Modern Unicode handling means documents in complex scripts — Arabic, Chinese, Devanagari — are properly supported with correct text extraction and reading order.
Complex structure
Comprehensive structure element attribute requirements mean that layout information (column spans, row groups, header scope) is preserved in the tag tree, not just inferred from visual position.
Embedded files
The Associated Files feature allows supplementary content (data tables, source documents, multimedia) to be properly linked to their parent structure elements.
Validation
How we validate PDF/UA-2 conformance.
We validate every output document using veraPDF, the open-source PDF/A and PDF/UA validator maintained by the Open Preservation Foundation and the PDF Association.
veraPDF implements machine-verifiable checks for every "shall" statement in both PDF/UA-1 and PDF/UA-2 specifications, as well as the WTPDF 1.0 profile. It is the only open-source tool with full PDF/UA-2 validation support.
Every document we deliver has passed veraPDF validation before it reaches you. If any document fails validation, we reprocess it at no cost.