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Three fictional documents: one with a single revision, one whose second revision rewrote the printed total, and one that was signed before that happened — so the signature no longer covers the page.
What a revision actually is
PDF has a feature called incremental update. When an editor saves a change, it does not rewrite the document: it appends the objects that changed, plus a fresh cross-reference table, to the end of the file. A PDF saved three times contains all three states, one after another, and the earlier ones are still there to be read.
This is deliberate, and it is what makes digital signatures possible — a signature covers a defined range of bytes, and appending after it leaves that range intact and checkable. It is also why a document can quietly carry the version of itself that somebody meant to replace.
More than one revision is not a finding
Signing adds a revision. So does filling in a form field, stamping a document number, applying a payroll system's watermark, or opening the file in a viewer that saves on close. In a sample of published Brazilian public contracts, the country's signature infrastructure produced multi-revision documents by design — which is why the count alone tells you nothing.
What the timeline marks instead is which revision replaced page content, an image, or a page object — the changes that altered what a reader sees. A revision that only added a signature dictionary and some bookkeeping is drawn without that mark, because it did not change the document; it attested to it.
What it cannot tell you
A timeline invites a story the data does not support. Three limits, stated before you read one into it.
- Not which tool made each save. A PDF records one producer and one creator for the whole file, not one per revision. The page shows that string once, labelled as document-level. Any tool that names a different program per revision is inventing it.
- Not when each save happened. The two dates a PDF carries — creation and modification — are document-level too, and both are editable text fields. There is no per-revision clock.
- Not what the earlier version said. The timeline reports which objects a revision replaced, by kind and number, not the words that changed. If you hold the original, comparison answers that question properly: it can show that one file provably contains the other, and name exactly what the appended objects overwrote.
When the chain is worth acting on
A document that claims to be an original and carries several saves, the last of which rewrote page content, is a document worth a question — not an accusation. Ask for the issuer's own download. The edited-PDF guide walks the signals that usually accompany it, and the field guide lists every family with its benign causes. As everywhere on this site: these are signals, never a verdict.