Visual upgrade enables users to retain the existing look and feel of SharePoint sites after an upgrade to a new version. This reduces the impact of the upgrade on users and also minimizes issues with customized pages, Web Parts, Web controls, and views.
Site owners can decide if and when to upgrade the appearance of their sites to the new version. By default, new sites that are created after the upgrade will use the new user experience.
Select this option if you want to change the existing SharePoint sites to use the new user experience, including layout, command organization, and style. If you select this option, you must also select one of the following options:
Select this option if you want to change the existing SharePoint sites to use the new user experience, but you want to preserve all the customized changes that you have made.
Select this option if you want to change the existing SharePoint sites to use the new user experience, and you want to overwrite all customized changes that you have made.
Select this option if you want to preserve the existing user experience, including layout, command organization, and style. All of the data and settings from the original site will be preserved.
After a farm upgrade, farm administrators, site collection administrators, and site owners can update their sites to the latest user experience.
While the site is using the previous user experience, some of the new features will not be available. These features include the Ribbon user interface, in-place editing for wiki pages, interactive calendars, and list relationships. When the site is updated to use the latest user experience, new features will automatically become available.
Regardless of the type of farm upgrade selected, administrators can take advantage of all the benefits of upgrade, including improved reliability, scalability, and manageability.
Preserving the previous user experience reduces the likelihood that customized content will cease to function. This ensures that administrators, developers, and end users can continue to use the SharePoint site until all upgrade work is completed.