If you choose to apply a new SAP, it will not immediately break your links, but there is a number of items to be observed by you:

• Any custom HTML Paste emails, or HTML blocks, will need to be manually updated Any AMPscript containing URL references would need to be updated
• Cloud Pages would have to be rebuilt on the new domain
• The prior SAP domain will remain in place for 60 days, but after this point, old links in emails and references to Cloud Pages on old domain will cease working.

Hence your links will remain operational until 60 days from your new SAP being applied on your account.

If you choose to apply a new SAP, it will not immediately break your links, but there is a number of items to be observed by you:

• Any custom HTML Paste emails, or HTML blocks, will need to be manually updated Any AMPscript containing URL references would need to be updated
• Cloud Pages would have to be rebuilt on the new domain
• The prior SAP domain will remain in place for 60 days, but after this point, old DNS records will no longer be held active by Salesforce, leading to links in emails and references to Cloud Pages on old domain will cease working.

Hence your links will remain operational until 60 days from your new SAP being applied on your account.