| Customization type | Recommendation |
| Site templates (.stp files) | Site templates (.stp files) are a deprecated feature in SharePoint Foundation 2010. New site templates in SharePoint Foundation 2010 are saved as .wsp files (solution packages). A site that was provisioned by using a site template will be upgraded, but you will be unable to create new sites that are based on that template. If you want to be able to create new sites, you can create and deploy a solution package instead. For more information, see Troubleshoot upgrade issues (SharePoint Foundation 2010). |
| Site definition | Migrate sites to a supported, predefined site definition, then apply custom features by using solution deployment. You can also continue to use a custom site definition. You do not have to create a new site definition that is based on SharePoint Foundation 2010. However, if you must perform custom upgrade actions for the definition, you might have to create an upgrade definition file for that site definition. For more information, see Upgrade Definition Files (http://go.microsoft.com/fwlink/?LinkId=182339) on MSDN. |
| "Fabulous 40" application templates | Microsoft is not creating new versions of these templates. Sites that are based on these templates can be upgraded, but make sure that you test each site before you upgrade the production environment. For more information, see Troubleshoot upgrade issues (SharePoint Foundation 2010). |
| Feature | Evaluate, then redesign or redeploy if necessary. |
| Workflows and server controls | Depends on the solution. Contact the vendor to find out whether there is an updated solution. If a workflow is compatible with the new version, redeploy. |
| Event handler | Rewrite and redeploy as a feature. |
| Managed paths (inclusions/exclusions) | Re-create inclusions for a database attach upgrade. Exclusions are assumed and do not have to be re-created. |
| Themes | Because of the extensive changes to the UI, custom themes that are based on Windows SharePoint Services 3.0 will not work in SharePoint Foundation 2010. Use Visual Upgrade to continue to use the sites in the old user experience until you can create and apply a new theme that is based on SharePoint Foundation 2010. |
| Toolbar actions | Move to the ribbon (Fluent UI). |
| Master pages and CSS files | Rework to accommodate the new user experience. |
| JavaScript | Test to determine whether any actions are required. In some cases, you might have to adjust the scripts to work with the new page model. Verify that it works on an upgraded site, and in both Visual Upgrade modes. |
| Search provider or security trimmer | Test to determine whether any actions are required. |
| Web Parts | Test to determine whether any actions are required. You might have to adjust the Web Parts to work with strict XHMTL mode. If a Web Part is located on a page but not in a Web Part Zone (so that it is, basically, HTML code embedded directly in a page), it will not work if you revert the page to the default template. |
| Services | Test to determine whether any actions are required. Redesign or adjust code, as needed. |
| Authentication providers | Test to determine whether any actions are required. Redeploy the provider on a test farm and ensure that it works correctly with claims authentication. |