Put the forum in maintenance mode

Where: Admin → System → Maintenance → Maintenance mode

Before you start

Non-admin visitors receive the notice with HTTP 503; administrators retain access to turn it off. Maintenance is temporary availability, not a private-category permission. The notice body uses the rich text editor.

Step by step

Write a Page heading/body, using {site} where the board name should appear.
Set Retry after seconds for crawlers.
Enable Put the board in maintenance mode and Save changes.
Check a private guest window; keep the admin session open.
When work is complete switch maintenance off and test guest access again.

Settings and behaviour

Maintenance mode

While this is on, every visitor who is not an administrator is shown the page below with a 503 status, so search engines know the board is coming back. Administrators keep the board, so you can switch it off again.	Control	What to enter / effect
Put the board in maintenance mode	The forum, the feeds and every page are replaced by the notice below until this is switched off. Initial default: `0`.

The maintenance page

What a visitor sees while the board is down. Use {site} for the board's name.	Control	What to enter / effect
Page heading	Left empty, the default heading is used. Initial default: `{site} is being maintained`.
Page body	Initial default: `<p>We are making a few changes. Please come back in a little while.</p>`.
Retry after (seconds)	Sent as the Retry-After header, so a crawler waits this long before checking again. Initial default: `3600`.

Check the result

Verify guest status/notice and successful reopening.

Common questions and troubleshooting

Admin sees full forum: expected bypass. Guest still sees notice after work: confirm maintenance is off and that a proxy is not caching the response.