Version history

The app keeps earlier versions of every wiki page, so a mistake can be undone. History in the page editor’s header lists them.

Who sees the history

Only the page’s editors: the same people who can edit the page (see Wiki overview). Readers, students included, never see earlier versions, not even of a page they can read: a version may hold a draft or text that was removed on purpose. For them the history’s address doesn’t exist.

When a version is kept

You don’t save versions yourself. A version is kept:

• when someone starts editing the page (the text as it was before);
• every 10 minutes while someone keeps typing;
• when you take over text someone else wrote;
• when you finish editing (leave the page);
• when a version is restored.

Typing in between is saved too, but it is not kept as a separate version.

The list

1. Open the page and select History in the header.
2. Versions are listed newest first and grouped by day. Each row shows:
   • what changed against the version before it, for example “Title changed · 2 blocks edited · 1 block added”;
   • who saved it, and the time (point at the time to see the full date);
   • Current version on the version that holds the page’s text now.
3. Select a row to open that version. The current version opens the editor.

A block is a paragraph, heading, list, code block, equation, image or note. A history holds 50 versions per page of the list; Older versions and Newer versions at the end move between them.

Viewing a version

A version opens read-only, the way readers saw it. Above it:

• the date and who saved it; a restored version also links to the version it brought back;
• This version shows the text;
• Compare with current shows what differs from the page now.

The arrows in the header open the previous and next versions.

Comparing

Compare with current goes through the page block by block:

Mark	Meaning
− on red, struck through	Only in this version: removed since.
+ on green, underlined	Added since.
~	The block was edited; inside it, removed words are struck through and added words underlined. Code is compared line by line.

A changed title is shown at the top. Unchanged blocks fold away; select “unchanged blocks” to unfold them. If nothing differs, the page says the version is the same as the current page.

Restoring a version

1. Open the version and select Restore this version in the header.
2. Read what will happen, then select Restore version.

The page’s title and text become the version’s, and the editor opens. The restore is a new version: nothing in the history is changed or removed, and the text the page had before is kept as a version too, so you can go back to it the same way.

• The page’s status (draft or published), its readers, owner and place in the tree don’t change.
• If the page is published, readers see the restored text at once.
• Anyone who is editing the page at that moment gets “Someone else changed this page.” and chooses whether to keep their own text (see “When several people edit a page” in Creating and editing pages).

What the history doesn’t record

The history keeps the title and the text. Moving a page in the tree, publishing, archiving and changes of readers or owner are not versions.

Deleting a page deletes its history as well (see Archiving and deleting).