PDF xref subsections vs multiple xref sections

[SeungheeB838]

I'm reading the PDF specifications and I'm not sure what the difference is between a PDF that has an xref with multiple subsections vs a PDF that has multiple xref sections. I see that both indicate that there has been incremental changes to the PDF but when would I create an entirely new xref section rather than create a new subsection to the existing one?

[Bernd Alheit]

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