Added preview mode info

windows/client-management/mdm/new-in-windows-mdm-enrollment-management.md

@@ -1398,8 +1398,8 @@ For details about Microsoft mobile device management protocols for Windows 10 s
 <ul>
 <li>ApplicationManagement/LaunchAppAfterLogOn</li>
 <li>ApplicationManagement/ScheduleForceRestartForUpdateFailures </li>
-<li>Authentication/EnableFastFirstSignIn</li>
+<li>Authentication/EnableFastFirstSignIn (Preview mode only)</li>
-<li>Authentication/EnableWebSignIn</li>
+<li>Authentication/EnableWebSignIn (Preview mode only)</li>
 <li>Authentication/PreferredAadTenantDomainName</li>
 <li>Browser/AllowFullScreenMode</li>
 <li>Browser/AllowPrelaunch</li>
@@ -1943,8 +1943,8 @@ The DM agent for [push-button reset](https://msdn.microsoft.com/windows/hardware
 <ul>
 <li>ApplicationManagement/LaunchAppAfterLogOn</li>
 <li>ApplicationManagement/ScheduleForceRestartForUpdateFailures </li>
-<li>Authentication/EnableFastFirstSignIn</li>
+<li>Authentication/EnableFastFirstSignIn (Preview mode only)</li>
-<li>Authentication/EnableWebSignIn</li>
+<li>Authentication/EnableWebSignIn (Preview mode only)</li>
 <li>Authentication/PreferredAadTenantDomainName</li>
 <li>Defender/CheckForSignaturesBeforeRunningScan</li>
 <li>Defender/DisableCatchupFullScan </li>

windows/client-management/mdm/policy-configuration-service-provider.md

@@ -364,10 +364,10 @@ The following diagram shows the Policy configuration service provider in tree fo
     <a href="./policy-csp-authentication.md#authentication-allowsecondaryauthenticationdevice" id="authentication-allowsecondaryauthenticationdevice">Authentication/AllowSecondaryAuthenticationDevice</a>
   </dd>
   <dd>
-    <a href="./policy-csp-authentication.md#authentication-enablefastfirstsignin" id="authentication-enablefastfirstsignin">Authentication/EnableFastFirstSignIn</a>
+    <a href="./policy-csp-authentication.md#authentication-enablefastfirstsignin" id="authentication-enablefastfirstsignin">Authentication/EnableFastFirstSignIn</a> (Preview mode only)
   </dd>
   <dd>
-    <a href="./policy-csp-authentication.md#authentication-enablewebsignin" id="authentication-enablewebsignin">Authentication/EnableWebSignIn</a>
+    <a href="./policy-csp-authentication.md#authentication-enablewebsignin" id="authentication-enablewebsignin">Authentication/EnableWebSignIn</a> (Preview mode only)
   </dd>
   <dd>
     <a href="./policy-csp-authentication.md#authentication-preferredaadtenantdomainname" id="authentication-preferredaadtenantdomainname">Authentication/PreferredAadTenantDomainName</a>

windows/client-management/mdm/policy-csp-authentication.md

@@ -354,6 +354,9 @@ The following list shows the supported values:
 
 <!--/Scope-->
 <!--Description-->
+> [!Warning]
+> This is policy is in preview mode and therefore not meant or recommended for production purposes.
+
 This policy is intended for use on Shared PCs to enable a quick first sign-in experience for a user. It works by automatically connecting new non-admin Azure Active Directory (Azure AD) accounts to the pre-configured candidate local accounts.
 
 Value type is integer. Supported values:
@@ -412,9 +415,12 @@ Value type is integer. Supported values:
 
 <!--/Scope-->
 <!--Description-->
+> [!Warning]
+> This is policy is in preview mode and therefore not meant or recommended for production purposes.
+
 "Web Sign-in" is a new way of signing into a Windows PC. It enables Windows logon support for non-ADFS federated providers (e.g. SAML). 
 
-> [!Note]  
+> [!Note]
 > Web Sign-in is only supported on Azure AD Joined PCs.
 
 Value type is integer. Supported values:
@@ -514,4 +520,4 @@ Footnotes:
 - 3 - Added in Windows 10, version 1709.
 - 4 - Added in Windows 10, version 1803.
 - 5 - Added in Windows 10, version 1809.
-- 6 - Added in the next major release of Windows 10.
+- 6 - Added in Windows 10, version 1903.