PDF 2.0 allows an arbitrary amount of information to appear before the PDF 2.0 data starts. For now we are setting a max offset of 4096 bytes from the BOF before we expect to see the %PDF-2.0 tag as this should encompass most use-cases and also maintain processing efficiency for any identification tools using PRONOM data. If you find this offset is inadequate please contact the PRONOM team. Also seeking EOF sequence %%EOF within final 1024 bytes.
This signature cannot currently identify files that were incrementally saved to PDF 2.0 from a previous PDF version (for example PDF 1.7), and this scenario will currently return an identification for the orignal format. Please contact the PRONOM team if you can assist with developing a signature that can account for such a use-case.
Details: File format summary
: detailed report on file format 
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