This is also known as beta feature management. The following are the salient characteristics of this feature:

• If you've been invited to try an LCS preview, you can enter a code or enable the preview here
• Public previews are available for any LCS user
• Private previews are available only to users and organizations that have been invited to participate
• To get involved in LCS previews, you can sign up for the Dynamics 365 for Finance and Operations, Enterprise edition feedback programs