diff --git a/eng/dependencies.props b/eng/dependencies.props
index d9cd74601f24..accbcb8e5f4e 100644
--- a/eng/dependencies.props
+++ b/eng/dependencies.props
@@ -9,10 +9,10 @@
        These ref versions are pulled from https://github.com/dotnet/versions.
   -->
   <PropertyGroup>
-    <CoreFxCurrentRef>c9274882c2f1e70586d6bffd6edb91833cc41ebd</CoreFxCurrentRef>
-    <CoreClrCurrentRef>c9274882c2f1e70586d6bffd6edb91833cc41ebd</CoreClrCurrentRef>
-    <ProjectNTfsCurrentRef>9ac7399739f61f6e5b5a159b000a71006641a751</ProjectNTfsCurrentRef>
-    <ProjectNTfsTestILCCurrentRef>9ac7399739f61f6e5b5a159b000a71006641a751</ProjectNTfsTestILCCurrentRef>
+    <CoreFxCurrentRef>528234f0de15b714b0f439f77285196e6d932cf7</CoreFxCurrentRef>
+    <CoreClrCurrentRef>528234f0de15b714b0f439f77285196e6d932cf7</CoreClrCurrentRef>
+    <ProjectNTfsCurrentRef>528234f0de15b714b0f439f77285196e6d932cf7</ProjectNTfsCurrentRef>
+    <ProjectNTfsTestILCCurrentRef>528234f0de15b714b0f439f77285196e6d932cf7</ProjectNTfsTestILCCurrentRef>
     <SniCurrentRef>8bd1ec5fac9f0eec34ff6b34b1d878b4359e02dd</SniCurrentRef>
     <StandardCurrentRef>9004703a1923e5c5582ceb8d79712df777412446</StandardCurrentRef>
     <BuildToolsCurrentRef>984a541f1d8f243a704fe4074e4b60c6cc3278f7</BuildToolsCurrentRef>
@@ -30,13 +30,13 @@
 
   <!-- Tests/infrastructure dependency versions. -->
   <PropertyGroup>
-    <CoreFxExpectedPrerelease>preview.19063.1</CoreFxExpectedPrerelease>
-    <MicrosoftNETCorePlatformsPackageVersion>3.0.0-preview.19063.1</MicrosoftNETCorePlatformsPackageVersion>
-    <MicrosoftNETCoreRuntimeCoreCLRPackageVersion>3.0.0-preview-27312-01</MicrosoftNETCoreRuntimeCoreCLRPackageVersion>
-    <MicrosoftNetCoreIlasmPackageVersion>3.0.0-preview-27312-01</MicrosoftNetCoreIlasmPackageVersion>
-    <ProjectNTfsExpectedPrerelease>beta-27311-00</ProjectNTfsExpectedPrerelease>
-    <ProjectNTfsTestILCExpectedPrerelease>beta-27311-00</ProjectNTfsTestILCExpectedPrerelease>
-    <ProjectNTfsTestILCPackageVersion>1.0.0-beta-27311-00</ProjectNTfsTestILCPackageVersion>
+    <CoreFxExpectedPrerelease>preview.19064.4</CoreFxExpectedPrerelease>
+    <MicrosoftNETCorePlatformsPackageVersion>3.0.0-preview.19064.4</MicrosoftNETCorePlatformsPackageVersion>
+    <MicrosoftNETCoreRuntimeCoreCLRPackageVersion>3.0.0-preview-27315-01</MicrosoftNETCoreRuntimeCoreCLRPackageVersion>
+    <MicrosoftNetCoreIlasmPackageVersion>3.0.0-preview-27315-01</MicrosoftNetCoreIlasmPackageVersion>
+    <ProjectNTfsExpectedPrerelease>beta-27315-00</ProjectNTfsExpectedPrerelease>
+    <ProjectNTfsTestILCExpectedPrerelease>beta-27315-00</ProjectNTfsTestILCExpectedPrerelease>
+    <ProjectNTfsTestILCPackageVersion>1.0.0-beta-27315-00</ProjectNTfsTestILCPackageVersion>
 
     <!-- CoreFX-built SNI identity package -->
     <RuntimeNativeSystemDataSqlClientSniPackageVersion>4.4.0</RuntimeNativeSystemDataSqlClientSniPackageVersion>
diff --git a/global.json b/global.json
index bffb5fcb9644..9437cacdd56d 100644
--- a/global.json
+++ b/global.json
@@ -5,6 +5,6 @@
   "msbuild-sdks": {
     "Microsoft.DotNet.Arcade.Sdk": "1.0.0-beta.19064.4",
     "Microsoft.DotNet.Helix.Sdk": "2.0.0-beta.19064.4",
-    "Microsoft.NET.Sdk.IL": "3.0.0-preview-27312-01"
+    "Microsoft.NET.Sdk.IL": "3.0.0-preview-27315-01"
   }
 }
diff --git a/src/System.Diagnostics.StackTrace/src/System.Diagnostics.StackTrace.csproj b/src/System.Diagnostics.StackTrace/src/System.Diagnostics.StackTrace.csproj
index ef96fba5a03e..9e4810245cac 100644
--- a/src/System.Diagnostics.StackTrace/src/System.Diagnostics.StackTrace.csproj
+++ b/src/System.Diagnostics.StackTrace/src/System.Diagnostics.StackTrace.csproj
@@ -38,9 +38,6 @@
   <ItemGroup Condition="'$(TargetsAOT)'!='true'">
     <Compile Include="System\Diagnostics\StackFrameExtensions.cs" />
   </ItemGroup>
-  <ItemGroup Condition="'$(TargetsAOT)'=='true'">
-    <Compile Include="System\Diagnostics\SymbolStore\ISymbolDocumentWriter.cs" />
-  </ItemGroup>
   <ItemGroup>
     <ReferenceFromRuntime Include="System.Private.CoreLib" />
   </ItemGroup>
diff --git a/src/System.Diagnostics.StackTrace/src/System/Diagnostics/SymbolStore/ISymbolDocumentWriter.cs b/src/System.Diagnostics.StackTrace/src/System/Diagnostics/SymbolStore/ISymbolDocumentWriter.cs
deleted file mode 100644
index d5b9552e5e39..000000000000
--- a/src/System.Diagnostics.StackTrace/src/System/Diagnostics/SymbolStore/ISymbolDocumentWriter.cs
+++ /dev/null
@@ -1,12 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-namespace System.Diagnostics.SymbolStore
-{
-    public interface ISymbolDocumentWriter
-    {
-        void SetCheckSum(System.Guid algorithmId, byte[] checkSum);
-        void SetSource(byte[] source);
-    }
-}
diff --git a/src/System.Memory/src/ApiCompatBaseline.uapaot.txt b/src/System.Memory/src/ApiCompatBaseline.uapaot.txt
deleted file mode 100644
index 8695142337c5..000000000000
--- a/src/System.Memory/src/ApiCompatBaseline.uapaot.txt
+++ /dev/null
@@ -1 +0,0 @@
-TypesMustExist : Type 'System.Buffers.OperationStatus' does not exist in the implementation but it does exist in the contract.
\ No newline at end of file
diff --git a/src/System.Memory/src/System.Memory.csproj b/src/System.Memory/src/System.Memory.csproj
index 55fadc8dc8ae..773dbae2cdb9 100644
--- a/src/System.Memory/src/System.Memory.csproj
+++ b/src/System.Memory/src/System.Memory.csproj
@@ -13,7 +13,6 @@
     <Compile Include="System\Buffers\BuffersExtensions.cs" />
     <Compile Include="System\Buffers\IBufferWriter.cs" />
     <Compile Include="System\Buffers\MemoryPool.cs" />
-    <Compile Include="System\Buffers\OperationStatus.cs" Condition="'$(TargetsAot)' == 'true'" /> <!-- TODO: Delete once .NET Native has OperationStatus in CoreLib -->
     <Compile Include="System\Buffers\ReadOnlySequence.cs" />
     <Compile Include="System\Buffers\ReadOnlySequenceDebugView.cs" />
     <Compile Include="System\Buffers\ReadOnlySequenceSegment.cs" />
diff --git a/src/System.Memory/src/System/Buffers/OperationStatus.cs b/src/System.Memory/src/System/Buffers/OperationStatus.cs
deleted file mode 100644
index e9ddcab57148..000000000000
--- a/src/System.Memory/src/System/Buffers/OperationStatus.cs
+++ /dev/null
@@ -1,34 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-namespace System.Buffers
-{
-    /// <summary>
-    /// This enum defines the various potential status that can be returned from Span-based operations
-    /// that support processing of input contained in multiple discontiguous buffers.
-    /// </summary>
-    public enum OperationStatus
-    {
-        /// <summary>
-        /// The entire input buffer has been processed and the operation is complete.
-        /// </summary>
-        Done,
-        /// <summary>
-        /// The input is partially processed, up to what could fit into the destination buffer.
-        /// The caller can enlarge the destination buffer, slice the buffers appropriately, and retry.
-        /// </summary>
-        DestinationTooSmall,
-        /// <summary>
-        /// The input is partially processed, up to the last valid chunk of the input that could be consumed.
-        /// The caller can stitch the remaining unprocessed input with more data, slice the buffers appropriately, and retry.
-        /// </summary>
-        NeedMoreData,
-        /// <summary>
-        /// The input contained invalid bytes which could not be processed. If the input is partially processed,
-        /// the destination contains the partial result. This guarantees that no additional data appended to the input
-        /// will make the invalid sequence valid.
-        /// </summary>
-        InvalidData,
-    }
-}
diff --git a/src/System.Runtime/tests/System/TimeSpanTests.cs b/src/System.Runtime/tests/System/TimeSpanTests.cs
index 031caf375b58..a81e4a0f3348 100644
--- a/src/System.Runtime/tests/System/TimeSpanTests.cs
+++ b/src/System.Runtime/tests/System/TimeSpanTests.cs
@@ -538,7 +538,14 @@ public static IEnumerable<object[]> Parse_Valid_TestData()
             yield return new object[] { "1:1:1.00001", CultureInfo.InvariantCulture, new TimeSpan(36610000100) };
             yield return new object[] { "1:1:1.000001", CultureInfo.InvariantCulture, new TimeSpan(36610000010) };
             yield return new object[] { "1:1:1.0000001", CultureInfo.InvariantCulture, new TimeSpan(36610000001) };
-            yield return new object[] { "1:1:1.00000001", CultureInfo.InvariantCulture, new TimeSpan(36610000001) };
+
+            if (PlatformDetection.IsFullFramework)
+            {
+                // Full framework can produce some incorrect results in some cases involving leading zeros when
+                // parsing fraction more than 7 digits. we test the expected full framework results here and we have
+                // have more net core tests to validate the correct the results.
+                yield return new object[] { "1:1:1.00000001", CultureInfo.InvariantCulture, new TimeSpan(36610000001) };
+            }
 
             // DD.HH:MM:SS
             yield return new object[] { "1.12:24:02", null, new TimeSpan(1, 12, 24, 2, 0) };
@@ -560,7 +567,14 @@ public static IEnumerable<object[]> Parse_Valid_TestData()
             yield return new object[] { "1:1:.00001", CultureInfo.InvariantCulture, new TimeSpan(36600000100) };
             yield return new object[] { "1:1:.000001", CultureInfo.InvariantCulture, new TimeSpan(36600000010) };
             yield return new object[] { "1:1:.0000001", CultureInfo.InvariantCulture, new TimeSpan(36600000001) };
-            yield return new object[] { "1:1:.00000001", CultureInfo.InvariantCulture, new TimeSpan(36600000001) };
+
+            if (PlatformDetection.IsFullFramework)
+            {
+                // Full framework can produce some incorrect results in some cases involving leading zeros when
+                // parsing fraction more than 7 digits. we test the expected full framework results here and we have
+                // have more net core tests to validate the correct the results.
+                yield return new object[] { "1:1:.00000001", CultureInfo.InvariantCulture, new TimeSpan(36600000001) };
+            }
 
             // Just below overflow on various components
             yield return new object[] { "10675199", null, new TimeSpan(9223371936000000000) };
@@ -625,7 +639,16 @@ public static IEnumerable<object[]> Parse_Invalid_TestData()
 
             // OverflowExceptions
             yield return new object[] { "1:1:1.99999999", null, typeof(OverflowException) }; // overflowing fraction
-            yield return new object[] { "1:1:1.000000001", null, typeof(OverflowException) }; // too many leading zeroes in fraction
+
+            if (PlatformDetection.IsFullFramework)
+            {
+                // on non full framework we now succeed parsing the fraction .000000001
+                // Full framework can produce some incorrect results in some cases involving leading zeros when
+                // parsing fraction more than 7 digits. we test the expected full framework results here and we have
+                // have more net core tests to validate the correct the results.
+                yield return new object[] { "1:1:1.000000001", null, typeof(OverflowException) }; // too many leading zeroes in fraction
+            }
+
             yield return new object[] { "2147483647", null, typeof(OverflowException) }; // overflowing value == int.MaxValue
             yield return new object[] { "2147483648", null, typeof(OverflowException) }; // overflowing value == int.MaxValue + 1
             yield return new object[] { "10675200", null, typeof(OverflowException) }; // overflowing number of days
@@ -809,15 +832,15 @@ public static void ParseExactTest_Invalid(string input, string format, Type exce
         {
             Assert.Throws(exceptionType, () => TimeSpan.ParseExact(input, format, new CultureInfo("en-US")));
             Assert.Throws(exceptionType, () => TimeSpan.ParseExact(input, format, new CultureInfo("en-US"), TimeSpanStyles.None));
-            
+
             Type exceptionTypeMultiple = exceptionType == typeof(OverflowException) || string.IsNullOrEmpty(format) ? typeof(FormatException) : exceptionType;
             Assert.Throws(exceptionTypeMultiple, () => TimeSpan.ParseExact(input, new string[] { format }, new CultureInfo("en-US")));
             Assert.Throws(exceptionTypeMultiple, () => TimeSpan.ParseExact(input, new string[] { format }, new CultureInfo("en-US"), TimeSpanStyles.None));
-            
+
             TimeSpan result;
             Assert.False(TimeSpan.TryParseExact(input, format, new CultureInfo("en-US"), out result));
             Assert.Equal(TimeSpan.Zero, result);
-            
+
             Assert.False(TimeSpan.TryParseExact(input, format, new CultureInfo("en-US"), TimeSpanStyles.None, out result));
             Assert.Equal(TimeSpan.Zero, result);
 
diff --git a/src/System.Runtime/tests/System/TimeSpanTests.netcoreapp.cs b/src/System.Runtime/tests/System/TimeSpanTests.netcoreapp.cs
index e44e53d33dda..d89791da4521 100644
--- a/src/System.Runtime/tests/System/TimeSpanTests.netcoreapp.cs
+++ b/src/System.Runtime/tests/System/TimeSpanTests.netcoreapp.cs
@@ -22,6 +22,30 @@ private static IEnumerable<object[]> MultiplicationTestData()
             yield return new object[] {TimeSpan.MaxValue, 0.5, TimeSpan.FromTicks((long)(long.MaxValue * 0.5))};
         }
 
+        // ParseDifferentLengthFractionWithLeadingZerosData mainly testing the behavior we have fixed in net core
+        // which is the way we normalize the parsed fraction and possibly rounding it.
+        private static IEnumerable<object[]> ParseDifferentLengthFractionWithLeadingZerosData()
+        {
+            yield return new object[] {"00:00:00.00000001",   new TimeSpan(0)};
+            yield return new object[] {"00:00:00.00000005",   new TimeSpan(1)};
+            yield return new object[] {"00:00:00.09999999",   new TimeSpan(1_000_000)};
+            yield return new object[] {"00:00:00.0268435455", new TimeSpan(268435)};
+            yield return new object[] {"00:00:00.01",         new TimeSpan(1_00_000)};
+            yield return new object[] {"0:00:00.01000000",    new TimeSpan(100_000)};
+            yield return new object[] {"0:00:00.010000000",   new TimeSpan(100_000)};
+            yield return new object[] {"0:00:00.0123456",     new TimeSpan(123456)};
+            yield return new object[] {"0:00:00.00123456",    new TimeSpan(12346)};
+            yield return new object[] {"0:00:00.00000098",    new TimeSpan(10)};
+            yield return new object[] {"0:00:00.00000099",    new TimeSpan(10)};
+        }
+
+        [Theory, MemberData(nameof(ParseDifferentLengthFractionWithLeadingZerosData))]
+        public static void Multiplication(string input, TimeSpan expected)
+        {
+            Assert.Equal(expected, TimeSpan.Parse(input, CultureInfo.InvariantCulture));
+            Assert.Equal(expected, TimeSpan.ParseExact(input, "g", CultureInfo.InvariantCulture));
+        }
+
         [Theory, MemberData(nameof(MultiplicationTestData))]
         public static void Multiplication(TimeSpan timeSpan, double factor, TimeSpan expected)
         {
diff --git a/src/System.Threading.Tasks/src/ApiCompatBaseline.netcoreappaot.txt b/src/System.Threading.Tasks/src/ApiCompatBaseline.netcoreappaot.txt
deleted file mode 100644
index 7f386254e2c8..000000000000
--- a/src/System.Threading.Tasks/src/ApiCompatBaseline.netcoreappaot.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-MembersMustExist : Member 'System.Threading.Tasks.TaskExtensions.ConfigureAwait<T>(System.Collections.Generic.IAsyncEnumerable<T>, System.Boolean)' does not exist in the implementation but it does exist in the contract.
-MembersMustExist : Member 'System.Threading.Tasks.TaskExtensions.WithCancellation<T>(System.Collections.Generic.IAsyncEnumerable<T>, System.Threading.CancellationToken)' does not exist in the implementation but it does exist in the contract.
\ No newline at end of file
diff --git a/src/System.Threading.Tasks/src/ApiCompatBaseline.uapaot.txt b/src/System.Threading.Tasks/src/ApiCompatBaseline.uapaot.txt
deleted file mode 100644
index 7f386254e2c8..000000000000
--- a/src/System.Threading.Tasks/src/ApiCompatBaseline.uapaot.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-MembersMustExist : Member 'System.Threading.Tasks.TaskExtensions.ConfigureAwait<T>(System.Collections.Generic.IAsyncEnumerable<T>, System.Boolean)' does not exist in the implementation but it does exist in the contract.
-MembersMustExist : Member 'System.Threading.Tasks.TaskExtensions.WithCancellation<T>(System.Collections.Generic.IAsyncEnumerable<T>, System.Threading.CancellationToken)' does not exist in the implementation but it does exist in the contract.
\ No newline at end of file
diff --git a/src/System.Threading.Tasks/src/System.Threading.Tasks.csproj b/src/System.Threading.Tasks/src/System.Threading.Tasks.csproj
index 0bbf9cba8a22..8e90d4ef3146 100644
--- a/src/System.Threading.Tasks/src/System.Threading.Tasks.csproj
+++ b/src/System.Threading.Tasks/src/System.Threading.Tasks.csproj
@@ -5,9 +5,6 @@
     <IsPartialFacadeAssembly>true</IsPartialFacadeAssembly>
     <Configurations>netcoreapp-Unix-Debug;netcoreapp-Unix-Release;netcoreapp-Windows_NT-Debug;netcoreapp-Windows_NT-Release;netcoreappaot-Windows_NT-Debug;netcoreappaot-Windows_NT-Release;uap-Windows_NT-Debug;uap-Windows_NT-Release;uapaot-Windows_NT-Debug;uapaot-Windows_NT-Release</Configurations>
   </PropertyGroup>
-  <ItemGroup Condition="'$(TargetsAot)' == 'true'"> <!-- TODO: Remove after .NET Native bits contain ConfiguredCancelableAsyncEnumerable -->
-    <Compile Include="$(CommonPath)\CoreLib\System\Runtime\CompilerServices\ConfiguredCancelableAsyncEnumerable.cs" />
-  </ItemGroup>
   <ItemGroup>
     <ReferenceFromRuntime Include="System.Private.CoreLib" />
   </ItemGroup>
diff --git a/src/shims/ApiCompatBaseline.uapaot.netstandard20.txt b/src/shims/ApiCompatBaseline.uapaot.netstandard20.txt
index c84194d2a7f2..42fed8a03b0e 100644
--- a/src/shims/ApiCompatBaseline.uapaot.netstandard20.txt
+++ b/src/shims/ApiCompatBaseline.uapaot.netstandard20.txt
@@ -40,7 +40,6 @@ TypesMustExist : Type 'System.Buffers.Binary.BinaryPrimitives' does not exist in
 TypesMustExist : Type 'System.Buffers.StandardFormat' does not exist in the implementation but it does exist in the contract.
 TypesMustExist : Type 'System.Buffers.Text.Utf8Formatter' does not exist in the implementation but it does exist in the contract.
 TypesMustExist : Type 'System.Buffers.Text.Utf8Parser' does not exist in the implementation but it does exist in the contract.
-TypesMustExist : Type 'System.Buffers.OperationStatus' does not exist in the implementation but it does exist in the contract.
 
 CannotRemoveAttribute : Attribute 'System.ComponentModel.DefaultEventAttribute' exists on 'System.ComponentModel.BackgroundWorker' in the contract but not the implementation.
 CannotChangeAttribute : Attribute 'System.Diagnostics.SwitchLevelAttribute' on 'System.Diagnostics.BooleanSwitch' changed from '[SwitchLevelAttribute(typeof(bool))]' in the contract to '[SwitchLevelAttribute(typeof(Boolean))]' in the implementation.