The poster declared \DocumentMetadata with pdfstandard=ua-2 and patched
the frametitle template to emit H1 tags. On TeX Live 2024 that produced
an untagged PDF carrying an accessibility claim it did not meet. On TeX
Live 2025, which is what Overleaf runs, it does not build at all:
! Class beamer Error: The beamer class is not compatible with
\DocumentMetadata
The LaTeX Tagging Project lists beamer and beamerposter as no-support,
meaning incompatible and not expected to change, and beamerposter pulls
in textpos and subfig which are incompatible in their own right. There
is no fix available, so the template now makes no claim and says why.
Removing the block also gets the poster building again.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Enables \DocumentMetadata (pdfversion=2.0, pdfstandard=ua-2) and
tagpdf with activate-all. Adds an H1 structure tag around every
frame title via \addtobeamertemplate, wraps the overlay-only tikz
helpers (\marktopleft, \markbottomright, \credit) in artifact tags
so they don't pollute the reading order, and adds alt text to each
\includegraphics. Verified compliant with verapdf's PDF/UA-2 profile.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
\DeclareLanguageMapping and \defbibheading come from biblatex, which the
template does not load. The template has failed to compile without local
edits for some time as a result.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
