Umbraco Upgrade v13 -> v17

No direct upgrade path!

Igloo 17 overhauls the way widgets are used on a page to utilise Umbraco's Block Grid system. The greatly improved editor usability and customisation potential to make more exciting layouts. Along with a new theme system to style your sites with unlimited Palettes.

Re-add your Igloo License.Key

You will see a no valid license at this point and an empty document, so you will need to copy your igloo.key file containing your license from the previous install. It goes in the umbraco/licenses folder. Or you can re-add via the backoffice also.

Igloo Customisations

If you have customized the Igloo CSS beyond the inbuilt Igloo theming engine, you will now have to merge your changes from your previous site.

If you have created additional widgets, these will also need to be migrated, you will need to migrate your views and associated code from the previous site to block grid. Add your widgets to the Igloo - Contnet - Block Grid data-type

Functionality beyond Igloo

If you have other functionality above and beyond core Igloo, you will also have to revisit that to update to the v17 standards.