Do I need to reprint codes when I change a guide?

No. Each QR code points to a guide or section, not to a copy of it. When you edit and save, the same printed code shows the new version straight away.

When a code stops showing content

• The section was deleted: its code opens the whole guide instead, with a note saying that part has been removed.
• The guide was deleted: its codes show "This guide has been removed".
• The guide was unpublished: its codes show "not available yet" until it's published again.
• The facility was deleted: its codes stop working.
• The facility is on Free: section codes open the whole guide. Codes for individual sections need a Basic or Pro licence.
• The facility's licence no longer covers it: see Why something says Hidden from visitors.

Codes are never reused, so an old sticker can never open someone else's guide.