Selecting two versions
- Open the audit log or a page's history (see Viewing Version History).
- Tick the Compare checkbox on two versions. Once two are ticked the remaining checkboxes are disabled.
- Click Compare selected.
The two versions do not have to belong to the same page, although comparing versions of different pages is rarely useful. You can also open a diff directly at /admin/page-versioning/diff?v1={id}&v2={id}. If one ID is missing, you are sent back to the history list with a reminder to select two versions.
Reading the diff
The diff page is headed "Diff: version #A → #B". The older version is always shown on the left and the newer on the right, whatever order you ticked them in, so additions are always green and removals always red.
At the top are two cards with each version's title, save time, editor and operation, each with a View full snapshot link. Between them is a similarity percentage for the two text renderings.
Below is a four-column table: old line number, old content, new line number, new content. Rows are coloured:
| Colour | Meaning |
|---|---|
| Red, struck through | Line present only in the older version |
| Green | Line present only in the newer version |
| No colour | Line unchanged |
If nothing differs, the page says "The two versions are identical."
What is compared
Each version is turned into plain text before diffing:
Title: About the collection
Slug: about
Public: yes
--- Block 1 [html] ---
Welcome to the archive.
...
- HTML blocks have their tags stripped, with
<br>,</p>,</div>and</li>turned into line breaks, so the diff shows wording changes rather than markup. - Every other block type (media, browse preview, and so on) is shown as pretty-printed JSON of its data, so changes to block settings are visible.
- Page layout and block layout data are not part of the text and do not show up in the diff.
The comparison is line based. A change inside one line appears as a removed line followed by an added line rather than a character-level highlight. Content longer than 5,000 lines is truncated and a note is added at the end of the diff.