Enable a temporary page
Install/enable the reviewed Coming Soon / Maintenance module and open System → Maintenance. Both its module switch and Enable the public upgrade page setting must be on. Choose Maintenance or Coming soon, title, plain message and up to five full HTTPS portal buttons. Blank optional button rows are removed. Preview the saved page before enabling it.
Maintenance returns HTTP 503 with the configured Retry-After. Coming soon returns HTTP 200. Both temporary responses are private/noncached and excluded from indexing. Turning either required switch off restores normal public access while retaining settings.
Access during maintenance
Visitors and customer sessions see the temporary page across storefront, sign-in and account routes. Active MFA-complete staff can keep working through their authorised session. Admin sign-in, payment webhook handling, first-party assets and site ownership verification remain available. The gate must not block a processor callback merely because customers see an upgrade message.
If module integrity fails while the gate is enabled, the core keeps the public gate active and reports the problem. It does not execute changed addon code to reopen the site.
Cross-storefront preview
Use Preview storefronts to inspect a verified destination with bounded staff handoff rather than sharing administrator cookies across domains. Preview is for staff review; it does not make a customer a staff member or grant an impersonated session security permissions. End the preview when finished and confirm ordinary visitor behavior separately.
Reopen responsibly
Confirm legal seller, real product prices, verified security/billing mail, payment/provider readiness and expected hostname before reopening checkout. A temporary page is not a database migration or backup procedure. See backup and restore before a release change.