Merge branch 'release/3.1' into merge/release/3.0-to-release/3.1

diff --combined eng/Version.Details.xml
index 34c1f96,4a4a7f8..29d797f
--- 1/eng/Version.Details.xml
--- 2/eng/Version.Details.xml
+++ b/eng/Version.Details.xml
@@@ -18,23 -18,23 +18,23 @@@
        <Uri>https://github.com/dotnet/arcade</Uri>
        <Sha>f5ccfdcbd828383d39cf583086ef42d72ca5b320</Sha>
      </Dependency>
-     <Dependency Name="Microsoft.Private.CoreFx.NETCoreApp" Version="4.6.0-rc2.19460.1">
+     <Dependency Name="Microsoft.Private.CoreFx.NETCoreApp" Version="4.7.0-preview1.19459.13">
        <Uri>https://github.com/dotnet/corefx</Uri>
-       <Sha>1f43072465d4be9920ab04a3c3ad91f82144de4e</Sha>
+       <Sha>2d38da41c8c153e498ea5fbda88c7532389b2f3f</Sha>
      </Dependency>
-     <Dependency Name="Microsoft.NETCore.Platforms" Version="3.0.0-rc2.19460.1">
+     <Dependency Name="Microsoft.NETCore.Platforms" Version="3.1.0-preview1.19459.13">
        <Uri>https://github.com/dotnet/corefx</Uri>
-       <Sha>1f43072465d4be9920ab04a3c3ad91f82144de4e</Sha>
+       <Sha>2d38da41c8c153e498ea5fbda88c7532389b2f3f</Sha>
      </Dependency>
      <Dependency Name="Microsoft.NETCore.App" Version="3.1.0-preview1.19459.38">
        <Uri>https://github.com/dotnet/core-setup</Uri>
        <Sha>0d6763312a2754e45d604ebdc69c8ac7e21a2187</Sha>
      </Dependency>
 -    <Dependency Name="optimization.IBC.CoreCLR" Version="99.99.99-master-20190909.1">
 +    <Dependency Name="optimization.IBC.CoreCLR" Version="99.99.99-master-20190910.1">
        <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-optimization</Uri>
        <Sha>48fd58c24cddbc6c0b0de1c00204aae1170f4864</Sha>
      </Dependency>
 -    <Dependency Name="optimization.PGO.CoreCLR" Version="99.99.99-master-20190909.1">
 +    <Dependency Name="optimization.PGO.CoreCLR" Version="99.99.99-master-20190910.1">
        <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-optimization</Uri>
        <Sha>48fd58c24cddbc6c0b0de1c00204aae1170f4864</Sha>
      </Dependency>

diff --combined eng/Versions.props
index 4640534,a971239..06542d9
--- 1/eng/Versions.props
--- 2/eng/Versions.props
+++ b/eng/Versions.props
@@@ -21,16 -21,16 +21,16 @@@
      <!-- roslyn -->
      <MicrosoftNetCompilersToolsetVersion>3.3.0-beta2-19367-02</MicrosoftNetCompilersToolsetVersion>
      <!-- corefx -->
-     <MicrosoftPrivateCoreFxNETCoreAppVersion>4.6.0-rc2.19460.1</MicrosoftPrivateCoreFxNETCoreAppVersion>
-     <MicrosoftNETCorePlatformsVersion>3.0.0-rc2.19460.1</MicrosoftNETCorePlatformsVersion>
+     <MicrosoftPrivateCoreFxNETCoreAppVersion>4.7.0-preview1.19459.13</MicrosoftPrivateCoreFxNETCoreAppVersion>
+     <MicrosoftNETCorePlatformsVersion>3.1.0-preview1.19459.13</MicrosoftNETCorePlatformsVersion>
      <MicrosoftBclAsyncInterfacesVersion>1.0.0-preview7.19326.2</MicrosoftBclAsyncInterfacesVersion>
      <!-- core-setup -->
      <MicrosoftNETCoreAppVersion>3.1.0-preview1.19459.38</MicrosoftNETCoreAppVersion>
      <!-- dotnet-core-internal-tooling -->
      <IbcMergePackageVersion>5.0.6-beta.19203.1</IbcMergePackageVersion>
      <!-- dotnet-optimization -->
 -    <optimizationIBCCoreCLRVersion>99.99.99-master-20190909.1</optimizationIBCCoreCLRVersion>
 -    <optimizationPGOCoreCLRVersion>99.99.99-master-20190909.1</optimizationPGOCoreCLRVersion>
 +    <optimizationIBCCoreCLRVersion>99.99.99-master-20190910.1</optimizationIBCCoreCLRVersion>
 +    <optimizationPGOCoreCLRVersion>99.99.99-master-20190910.1</optimizationPGOCoreCLRVersion>
    </PropertyGroup>
    <!--Package names-->
    <PropertyGroup>