diff --git a/build/dependencies.props b/build/dependencies.props
index f921daa167..a69c09b8d9 100644
--- a/build/dependencies.props
+++ b/build/dependencies.props
@@ -3,24 +3,24 @@
     <MSBuildAllProjects>$(MSBuildAllProjects);$(MSBuildThisFileFullPath)</MSBuildAllProjects>
   </PropertyGroup>
   <PropertyGroup Label="Package Versions">
-    <InternalAspNetCoreSdkPackageVersion>2.1.0-preview3-17018</InternalAspNetCoreSdkPackageVersion>
-    <MicrosoftAspNetCoreTestingPackageVersion>2.1.0-preview3-32233</MicrosoftAspNetCoreTestingPackageVersion>
-    <MicrosoftExtensionsActivatorUtilitiesSourcesPackageVersion>2.1.0-preview3-32233</MicrosoftExtensionsActivatorUtilitiesSourcesPackageVersion>
-    <MicrosoftExtensionsCopyOnWriteDictionarySourcesPackageVersion>2.1.0-preview3-32233</MicrosoftExtensionsCopyOnWriteDictionarySourcesPackageVersion>
-    <MicrosoftExtensionsDependencyInjectionPackageVersion>2.1.0-preview3-32233</MicrosoftExtensionsDependencyInjectionPackageVersion>
-    <MicrosoftExtensionsFileProvidersAbstractionsPackageVersion>2.1.0-preview3-32233</MicrosoftExtensionsFileProvidersAbstractionsPackageVersion>
-    <MicrosoftExtensionsLoggingAbstractionsPackageVersion>2.1.0-preview3-32233</MicrosoftExtensionsLoggingAbstractionsPackageVersion>
-    <MicrosoftExtensionsObjectPoolPackageVersion>2.1.0-preview3-32233</MicrosoftExtensionsObjectPoolPackageVersion>
-    <MicrosoftExtensionsOptionsPackageVersion>2.1.0-preview3-32233</MicrosoftExtensionsOptionsPackageVersion>
-    <MicrosoftExtensionsPrimitivesPackageVersion>2.1.0-preview3-32233</MicrosoftExtensionsPrimitivesPackageVersion>
-    <MicrosoftExtensionsWebEncodersSourcesPackageVersion>2.1.0-preview3-32233</MicrosoftExtensionsWebEncodersSourcesPackageVersion>
+    <InternalAspNetCoreSdkPackageVersion>2.1.0-rc1-15774</InternalAspNetCoreSdkPackageVersion>
+    <MicrosoftAspNetCoreTestingPackageVersion>2.1.0-rc1-30613</MicrosoftAspNetCoreTestingPackageVersion>
+    <MicrosoftExtensionsActivatorUtilitiesSourcesPackageVersion>2.1.0-rc1-30613</MicrosoftExtensionsActivatorUtilitiesSourcesPackageVersion>
+    <MicrosoftExtensionsCopyOnWriteDictionarySourcesPackageVersion>2.1.0-rc1-30613</MicrosoftExtensionsCopyOnWriteDictionarySourcesPackageVersion>
+    <MicrosoftExtensionsDependencyInjectionPackageVersion>2.1.0-rc1-30613</MicrosoftExtensionsDependencyInjectionPackageVersion>
+    <MicrosoftExtensionsFileProvidersAbstractionsPackageVersion>2.1.0-rc1-30613</MicrosoftExtensionsFileProvidersAbstractionsPackageVersion>
+    <MicrosoftExtensionsLoggingAbstractionsPackageVersion>2.1.0-rc1-30613</MicrosoftExtensionsLoggingAbstractionsPackageVersion>
+    <MicrosoftExtensionsObjectPoolPackageVersion>2.1.0-rc1-30613</MicrosoftExtensionsObjectPoolPackageVersion>
+    <MicrosoftExtensionsOptionsPackageVersion>2.1.0-rc1-30613</MicrosoftExtensionsOptionsPackageVersion>
+    <MicrosoftExtensionsPrimitivesPackageVersion>2.1.0-rc1-30613</MicrosoftExtensionsPrimitivesPackageVersion>
+    <MicrosoftExtensionsWebEncodersSourcesPackageVersion>2.1.0-rc1-30613</MicrosoftExtensionsWebEncodersSourcesPackageVersion>
     <MicrosoftNETCoreApp20PackageVersion>2.0.0</MicrosoftNETCoreApp20PackageVersion>
-    <MicrosoftNETCoreApp21PackageVersion>2.1.0-preview3-26413-05</MicrosoftNETCoreApp21PackageVersion>
+    <MicrosoftNETCoreApp21PackageVersion>2.1.0-rc1-26419-02</MicrosoftNETCoreApp21PackageVersion>
     <MicrosoftNETTestSdkPackageVersion>15.6.1</MicrosoftNETTestSdkPackageVersion>
-    <NETStandardLibrary20PackageVersion>2.0.1</NETStandardLibrary20PackageVersion>
     <MoqPackageVersion>4.7.49</MoqPackageVersion>
-    <SystemBuffersPackageVersion>4.5.0-preview3-26413-02</SystemBuffersPackageVersion>
-    <SystemTextEncodingsWebPackageVersion>4.5.0-preview3-26413-02</SystemTextEncodingsWebPackageVersion>
+    <NETStandardLibrary20PackageVersion>2.0.1</NETStandardLibrary20PackageVersion>
+    <SystemBuffersPackageVersion>4.5.0-rc1-26419-03</SystemBuffersPackageVersion>
+    <SystemTextEncodingsWebPackageVersion>4.5.0-rc1-26419-03</SystemTextEncodingsWebPackageVersion>
     <XunitAnalyzersPackageVersion>0.8.0</XunitAnalyzersPackageVersion>
     <XunitPackageVersion>2.3.1</XunitPackageVersion>
     <XunitRunnerVisualStudioPackageVersion>2.4.0-beta.1.build3945</XunitRunnerVisualStudioPackageVersion>
diff --git a/korebuild-lock.txt b/korebuild-lock.txt
index b419d767b9..9d4ef8c888 100644
--- a/korebuild-lock.txt
+++ b/korebuild-lock.txt
@@ -1,2 +1,2 @@
-version:2.1.0-preview3-17018
-commithash:af264ca131f212b5ba8aafbc5110fc0fc510a2be
+version:2.1.0-rc1-15774
+commithash:ed5ca9de3c652347dbb0158a9a65eff3471d2114