The current download of FreeBSD princexml 15 links to version 13 of libavif. Is it possible to link against /usr/local/lib/libavif.so.15? That's the file I get when installing version 0.11.1 from libavif.

root@ports-jeroenp:/usr/local/lib/prince/bin # ldd prince
prince:
        libxml2.so.2 => /usr/local/lib/libxml2.so.2 (0x822bf5000)
        libiconv.so.2 => /usr/local/lib/libiconv.so.2 (0x8237f1000)
        libtiff.so.5 => /usr/local/lib/libtiff.so.5 (0x8242e8000)
        libgif.so.7 => /usr/local/lib/libgif.so.7 (0x8252e2000)
        libpng16.so.16 => /usr/local/lib/libpng16.so.16 (0x82684c000)
        libwebp.so.7 => /usr/local/lib/libwebp.so.7 (0x825924000)
        libwebpdemux.so.2 => /usr/local/lib/libwebpdemux.so.2 (0x82829f000)
        libavif.so.13 => not found (0)

Thanks, we have updated the Prince package for FreeBSD, please download 15.0.1.

Excellent, this works! Thanks for the swift response.