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In 2016, we introduced a new “modern” experience for SharePoint, bringing extensibility, accessibility, and responsive design to a complete overhaul of the user experience. Since then, modern has been the center of innovation in SharePoint and OneDrive, although classic mode remains supported and available.

We’re making it easier for users to get to our latest feature updates.  Starting April 1, 2019, it will no longer be possible to restrict an entire organization (tenant) to classic mode for lists and libraries.   Lists and libraries may still use classic mode using the granular opt-out switches that we provide at the site collection, site, list, and library levels.  Additionally, lists that use certain features and customizations that are not supported by modern will still be automatically switched to classic mode.

After April 1, lists and libraries that are in classic mode as a result of tenant opt-out will automatically be shifted to modern.  Users will benefit from enhancements and new features such as attention views, PowerApps integration, Flow, column formatting, and the filters pane. 

If you still wish to restrict users to the classic experience, you have several tools to help you:

• Identify the impact. The SharePoint Modernization scanner identifies sites and lists that have customizations that are not supported by modern UI.  Although many of these lists will automatically remain in classic mode even after this change, you may wish to keep some sites running entirely in classic to avoid users switching between different experience modes within a single site.
• Disable modern experience for specific site collections. Administrators can use a PowerShell script to enable or disable the modern experience for a single site collection or for a list of site collections as provided by the SharePoint Modernization scanner.  Alternately, users can still use the “return to classic” option on modern views of lists or libraries to temporary return to classic, and list owners can use List Settings to configure that list to use the classic experience for all users.

Frequently asked Questions

What lists in my environment will be affected by this change?

Today, a list or library might appear in classic mode for any of these reasons:

1. The list is in a tenant that has opted out of modern lists via the tenant setting.
2. The list is in a site collection or site that has opted out of modern lists via PowerShell.
3. The list itself has opted out of modern lists through the list advanced setting.
4. The list has an unsupported template or customization that causes it to fall back to classic mode.  For example, if the list is a Calendar or Task list, or if the list has a JSLink customization applied.
5. The user has chosen “return to classic” from inside the modern view.

This change will only affect lists that are currently in classic mode as a result of #1 – because of the tenant opt-out switch.  Lists that have overlapping reasons will not be affected either.  For example, a calendar list in a tenant that’s opted out has reasons #1 and #4.  This list will not be affected by this change.

When will Microsoft remove or deprecate classic mode?

There are no plans to remove classic mode.  We’ll maintain the current feature set for classic lists and library experiences, but all our new feature innovation will be going into the modern interface.

Are there any other changes to user experiences as a result of this change?

This update is only a change to the administrative settings, not the user interface.  It makes it simpler to deploy modern experiences to more users, while providing enhanced tools to identify and manage lists and libraries that need to stay classic. 

I’m still using a calendar list that is only available in classic mode.  Why aren’t you modernizing these lists?

We’ve already modernized many classic scenarios, such as document sets.  At the same time, we’ve also released new modern-only features, such as Microsoft Flow integration.  Modernization is an ongoing process.  We evaluate many data sources to help set priorities – including usage data, customer meetings and UserVoice.  Features with the greatest impact and usage are updated before features with less usage or demand.

More modernizations will come.  We do recognize that individual needs may vary from collective priorities.  Microsoft is committed to updating all critical classic scenarios to the modern experience. 

I’m going to use my classic publishing portal for a long time because of features and investment. Is that going away?

Classic publishing remains a critical scenario for many customers.  Although we are not delivering new features, we are actively updating and optimizing performance for classic publishing features.

We’ve also released many updates for publishing modern pages and communication sites.  You can see examples of pages and sites in our new SharePoint lookbook.  More details about modern intranets are available on the TechCommunity Resource Center .

What other updates can we expect to modern experiences?

As mentioned earlier, we have already announced plans to release column totals and modern document sets early in 2019.  Expect to see many more updates announced here on the TechCommunity throughout 2019.

The above is kindly provided by the Microsoft Tech Community!