Basics
- Create a copy of your site, and only work on that
Prepare Templates
- Move all templates in the main folder into a subfolder "old"
- Adjust all view-configurations to point to the new location
- test the website to verify everything still works
Prepare Content-Types you want to Drop
- Add OLD to the front of the shown name so it's easy to spot these in the list
Prepare Content-Types you want to Upgrade
Do this only for the content-types which have a lot of data and which you want to keep in this schema. Don't do this for content-types whose data you'll manually copy paste anyhow.
- Verify the static name is the same as the static name of the upgrade you'll add later on (this may be very technical, make sure you know what you're doing)
- If the static name does not correspond, rename the old content type on the existing installation
- After changing the content type static name, re-assign the content type for all templates
- Review the field names of the old / new schema, and rename the old field names to match the new fields for import
- This will probably require that you also adjust the old templates to use the changed field names
- Verify everything still works