Migration process and timeframe

A website migration at the is not a one-size-fits-all process. Timelines will vary depending on the size and complexity of your website, the availability of resources within your team, and whether the necessary components have been developed in the new platform. 

This page outlines the typical phases involved in a migration, along with a practical checklist to help you plan and manage the process.

Migration timeline

While each department or unit will progress at its own pace, most migrations follow a similar set of stages. These may overlap depending on your approach.

Migration process

Migration from Mosaic to Fresco began in August 2025 with our Pioneers and needs to be completed by October 2026. Most sites will be migrated through 2026 as more functionality is added to Fresco.

For your site to be migrated, you'll need to:

• Confirm a tranche confirmation date
• Agree to some terms and conditions, and
• Attend a tranche kick off session.

For more detailed information un the Fresco migration process, please check out the Toolkit. Read the Go-live/initiating migration page.

We also recommend reading our Pre-Migration Prep guide to help you get ready for your migration, if you haven't already done so. Read our Pre-Migration page.

Once the migration has been done automatically, it is not uncommon for smaller or simpler sites to be reviewed in a matter of days or weeks, while larger or more complex sites may require months. 

The following estimates are based on an initial assessment of how much time would be required for one person to review and amend a site, following auto-migration from Mosaic to Fresco, in readiness for publication i.e. the step in green below. 

Estimates will be reviewed and amended, based on experience, as the migration process is rolled out.