diff --git a/samples/HelloWorld/project.json b/samples/HelloWorld/project.json
index 2bdad3b44c..2d80d1f40d 100644
--- a/samples/HelloWorld/project.json
+++ b/samples/HelloWorld/project.json
@@ -9,14 +9,17 @@
   },
   "frameworks": {
     "dnx451": {},
-    "dnxcore50": {
+    "netstandardapp1.5": {
       "dependencies": {
         "System.Collections": "4.0.11-*",
         "System.Console": "4.0.0-*",
         "System.Globalization": "4.0.11-*",
         "System.IO": "4.1.0-*",
         "System.Threading.Tasks": "4.0.11-*"
-      }
+      },
+      "imports": [
+        "dnxcore50"
+      ]
     }
   }
 }
\ No newline at end of file
diff --git a/samples/HotAddSample/project.json b/samples/HotAddSample/project.json
index 9eb1fe1013..dde0f7325a 100644
--- a/samples/HotAddSample/project.json
+++ b/samples/HotAddSample/project.json
@@ -13,6 +13,10 @@
   },
   "frameworks": {
     "dnx451": {},
-    "dnxcore50": {}
+    "netstandardapp1.5": {
+      "imports": [
+        "dnxcore50"
+      ]
+    }
   }
 }
\ No newline at end of file
diff --git a/samples/SelfHostServer/project.json b/samples/SelfHostServer/project.json
index ded562b37c..e31b464c7b 100644
--- a/samples/SelfHostServer/project.json
+++ b/samples/SelfHostServer/project.json
@@ -12,6 +12,10 @@
   },
   "frameworks": {
     "dnx451": {},
-    "dnxcore50": {}
+    "netstandardapp1.5": {
+      "imports": [
+        "dnxcore50"
+      ]
+    }
   }
 }
\ No newline at end of file
diff --git a/src/Microsoft.AspNetCore.Server.WebListener/project.json b/src/Microsoft.AspNetCore.Server.WebListener/project.json
index 3c73aa60b2..b2a504e17f 100644
--- a/src/Microsoft.AspNetCore.Server.WebListener/project.json
+++ b/src/Microsoft.AspNetCore.Server.WebListener/project.json
@@ -10,16 +10,21 @@
     "allowUnsafe": true,
     "warningsAsErrors": true,
     "keyFile": "../../tools/Key.snk",
-    "nowarn": [ "CS1591" ],
+    "nowarn": [
+      "CS1591"
+    ],
     "xmlDoc": true
   },
   "frameworks": {
     "net451": {},
-    "dotnet5.4": {
+    "netstandard1.3": {
       "dependencies": {
         "System.Security.Claims": "4.0.1-*"
       },
-      "imports": "portable-net451+win8"
+      "imports": [
+        "dotnet5.4",
+        "portable-net451+win8"
+      ]
     }
   }
 }
\ No newline at end of file
diff --git a/src/Microsoft.Net.Http.Server/NativeInterop/ComNetOS.cs b/src/Microsoft.Net.Http.Server/NativeInterop/ComNetOS.cs
index 11333417cb..e48bc24d6b 100644
--- a/src/Microsoft.Net.Http.Server/NativeInterop/ComNetOS.cs
+++ b/src/Microsoft.Net.Http.Server/NativeInterop/ComNetOS.cs
@@ -32,7 +32,7 @@ namespace Microsoft.Net.Http.Server
 
         static ComNetOS()
         {
-#if DOTNET5_4
+#if NETSTANDARD1_3
             // TODO: SkipIOCPCallbackOnSuccess doesn't work on Win7. Need a way to detect Win7 vs 8+.
             IsWin8orLater = false;
 #else
diff --git a/src/Microsoft.Net.Http.Server/NativeInterop/HttpSysSettings.cs b/src/Microsoft.Net.Http.Server/NativeInterop/HttpSysSettings.cs
index 46e3aee54d..946345193c 100644
--- a/src/Microsoft.Net.Http.Server/NativeInterop/HttpSysSettings.cs
+++ b/src/Microsoft.Net.Http.Server/NativeInterop/HttpSysSettings.cs
@@ -26,7 +26,7 @@ using System.Diagnostics;
 using System.Globalization;
 using System.IO;
 using System.Security;
-#if !DOTNET5_4
+#if !NETSTANDARD1_3
 using Microsoft.Win32;
 #endif
 
@@ -34,7 +34,7 @@ namespace Microsoft.Net.Http.Server
 {
     internal static class HttpSysSettings
     {
-#if !DOTNET5_4
+#if !NETSTANDARD1_3
         private const string HttpSysParametersKey = @"System\CurrentControlSet\Services\HTTP\Parameters";
 #endif
         private const bool EnableNonUtf8Default = true;
@@ -61,7 +61,7 @@ namespace Microsoft.Net.Http.Server
         }
 
         private static void ReadHttpSysRegistrySettings()
-#if DOTNET5_4
+#if NETSTANDARD1_3
         {
         }
 #else
diff --git a/src/Microsoft.Net.Http.Server/NativeInterop/NclUtilities.cs b/src/Microsoft.Net.Http.Server/NativeInterop/NclUtilities.cs
index 8c939d7bc2..7901200e79 100644
--- a/src/Microsoft.Net.Http.Server/NativeInterop/NclUtilities.cs
+++ b/src/Microsoft.Net.Http.Server/NativeInterop/NclUtilities.cs
@@ -32,7 +32,7 @@ namespace Microsoft.Net.Http.Server
             get
             {
                 return Environment.HasShutdownStarted
-#if !DOTNET5_4
+#if !NETSTANDARD1_3
                     || AppDomain.CurrentDomain.IsFinalizingForUnload()
 #endif
                     ;
diff --git a/src/Microsoft.Net.Http.Server/NativeInterop/UnsafeNativeMethods.cs b/src/Microsoft.Net.Http.Server/NativeInterop/UnsafeNativeMethods.cs
index e9171f7a8a..8329a27cab 100644
--- a/src/Microsoft.Net.Http.Server/NativeInterop/UnsafeNativeMethods.cs
+++ b/src/Microsoft.Net.Http.Server/NativeInterop/UnsafeNativeMethods.cs
@@ -33,7 +33,7 @@ namespace Microsoft.Net.Http.Server
     {
         private const string HTTPAPI = "httpapi.dll";
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
         private const string sspicli_LIB = "sspicli.dll";
         private const string api_ms_win_core_processthreads_LIB = "api-ms-win-core-processthreads-l1-1-1.dll";
         private const string api_ms_win_core_io_LIB = "api-ms-win-core-io-l1-1-1.dll";
@@ -63,21 +63,21 @@ namespace Microsoft.Net.Http.Server
             internal const uint ERROR_CONNECTION_INVALID = 1229;
         }
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
         [DllImport(api_ms_win_core_processthreads_LIB, ExactSpelling = true, CallingConvention = CallingConvention.StdCall, SetLastError = true)]
 #else
         [DllImport(KERNEL32, ExactSpelling = true, CallingConvention = CallingConvention.StdCall, SetLastError = true)]
 #endif
         internal static extern uint GetCurrentThreadId();
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
         [DllImport(api_ms_win_core_io_LIB, ExactSpelling = true, CallingConvention = CallingConvention.StdCall, SetLastError = true)]
 #else
         [DllImport(KERNEL32, ExactSpelling = true, CallingConvention = CallingConvention.StdCall, SetLastError = true)]
 #endif
         internal static unsafe extern uint CancelIoEx(SafeHandle handle, SafeNativeOverlapped overlapped);
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
         [DllImport(api_ms_win_core_kernel32_legacy_LIB, ExactSpelling = true, CallingConvention = CallingConvention.StdCall, SetLastError = true)]
 #else
         [DllImport(KERNEL32, ExactSpelling = true, CallingConvention = CallingConvention.StdCall, SetLastError = true)]
@@ -102,7 +102,7 @@ namespace Microsoft.Net.Http.Server
             [Out] out HeapAllocHandle resultList);
 
         // http://msdn.microsoft.com/en-us/library/windows/desktop/aa366569(v=vs.85).aspx
-#if DOTNET5_4
+#if NETSTANDARD1_3
         [DllImport(api_ms_win_core_heap_LIB, CallingConvention = CallingConvention.Winapi, SetLastError = true)]
 #else
         [DllImport(KERNEL32, CallingConvention = CallingConvention.Winapi, SetLastError = true)]
@@ -110,7 +110,7 @@ namespace Microsoft.Net.Http.Server
         internal static extern IntPtr GetProcessHeap();
 
         // http://msdn.microsoft.com/en-us/library/windows/desktop/aa366701(v=vs.85).aspx
-#if DOTNET5_4
+#if NETSTANDARD1_3
         [DllImport(api_ms_win_core_heap_LIB, CallingConvention = CallingConvention.Winapi, SetLastError = true)]
 #else
         [DllImport(KERNEL32, CallingConvention = CallingConvention.Winapi, SetLastError = true)]
@@ -122,7 +122,7 @@ namespace Microsoft.Net.Http.Server
 
         internal static class SafeNetHandles
         {
-#if DOTNET5_4
+#if NETSTANDARD1_3
             [DllImport(sspicli_LIB, ExactSpelling = true, SetLastError = true)]
 #else
             [DllImport(SECUR32, ExactSpelling = true, SetLastError = true)]
@@ -130,7 +130,7 @@ namespace Microsoft.Net.Http.Server
             internal static extern int FreeContextBuffer(
                 [In] IntPtr contextBuffer);
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
             [DllImport(sspicli_LIB, ExactSpelling = true, SetLastError = true)]
 #else
             [DllImport(SECUR32, ExactSpelling = true, SetLastError = true)]
@@ -147,21 +147,21 @@ namespace Microsoft.Net.Http.Server
             [DllImport(HTTPAPI, ExactSpelling = true, CallingConvention = CallingConvention.StdCall, SetLastError = true)]
             internal static extern unsafe uint HttpCloseRequestQueue(IntPtr pReqQueueHandle);
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
             [DllImport(api_ms_win_core_handle_LIB, ExactSpelling = true, SetLastError = true)]
 #else
             [DllImport(KERNEL32, ExactSpelling = true, SetLastError = true)]
 #endif
             internal static extern bool CloseHandle(IntPtr handle);
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
             [DllImport(api_ms_win_core_heap_obsolete_LIB, ExactSpelling = true, SetLastError = true)]
 #else
             [DllImport(KERNEL32, ExactSpelling = true, SetLastError = true)]
 #endif
             internal static extern SafeLocalFree LocalAlloc(int uFlags, UIntPtr sizetdwBytes);
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
             [DllImport(api_ms_win_core_heap_obsolete_LIB, EntryPoint = "LocalAlloc", SetLastError = true)]
 #else
             [DllImport(KERNEL32, EntryPoint = "LocalAlloc", SetLastError = true)]
@@ -169,21 +169,21 @@ namespace Microsoft.Net.Http.Server
 
             internal static extern SafeLocalFreeChannelBinding LocalAllocChannelBinding(int uFlags, UIntPtr sizetdwBytes);
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
             [DllImport(api_ms_win_core_heap_obsolete_LIB, ExactSpelling = true, SetLastError = true)]
 #else
             [DllImport(KERNEL32, ExactSpelling = true, SetLastError = true)]
 #endif
             internal static extern IntPtr LocalFree(IntPtr handle);
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
             [DllImport(api_ms_win_core_libraryloader_LIB, ExactSpelling = true, CharSet = CharSet.Unicode, SetLastError = true)]
 #else
             [DllImport(KERNEL32, ExactSpelling = true, CharSet = CharSet.Unicode, SetLastError = true)]
 #endif            
             internal static extern unsafe SafeLoadLibrary LoadLibraryExW([In] string lpwLibFileName, [In] void* hFile, [In] uint dwFlags);
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
             [DllImport(api_ms_win_core_libraryloader_LIB, ExactSpelling = true, SetLastError = true)]
 #else
             [DllImport(KERNEL32, ExactSpelling = true, SetLastError = true)]
diff --git a/src/Microsoft.Net.Http.Server/Overlapped/DeferredDisposableLifetime.cs b/src/Microsoft.Net.Http.Server/Overlapped/DeferredDisposableLifetime.cs
index 80ac921a01..a897da7d0e 100644
--- a/src/Microsoft.Net.Http.Server/Overlapped/DeferredDisposableLifetime.cs
+++ b/src/Microsoft.Net.Http.Server/Overlapped/DeferredDisposableLifetime.cs
@@ -1,4 +1,4 @@
-#if !DOTNET5_4 // TODO: Temp copy. Remove once we target net46.
+#if !NETSTANDARD1_3 // TODO: Temp copy. Remove once we target net46.
 using System;
 namespace System.Threading
 {
diff --git a/src/Microsoft.Net.Http.Server/Overlapped/IDeferredDisposable.cs b/src/Microsoft.Net.Http.Server/Overlapped/IDeferredDisposable.cs
index 57bf6b41f7..b45b7a2c8f 100644
--- a/src/Microsoft.Net.Http.Server/Overlapped/IDeferredDisposable.cs
+++ b/src/Microsoft.Net.Http.Server/Overlapped/IDeferredDisposable.cs
@@ -1,4 +1,4 @@
-#if !DOTNET5_4 // TODO: Temp copy. Remove once we target net46.
+#if !NETSTANDARD1_3 // TODO: Temp copy. Remove once we target net46.
 using System;
 namespace System.Threading
 {
diff --git a/src/Microsoft.Net.Http.Server/Overlapped/PreAllocatedOverlapped.cs b/src/Microsoft.Net.Http.Server/Overlapped/PreAllocatedOverlapped.cs
index 92572dc9f4..7d30b4e248 100644
--- a/src/Microsoft.Net.Http.Server/Overlapped/PreAllocatedOverlapped.cs
+++ b/src/Microsoft.Net.Http.Server/Overlapped/PreAllocatedOverlapped.cs
@@ -1,4 +1,4 @@
-#if !DOTNET5_4 // TODO: Temp copy. Remove once we target net46.
+#if !NETSTANDARD1_3 // TODO: Temp copy. Remove once we target net46.
 using System;
 namespace System.Threading
 {
diff --git a/src/Microsoft.Net.Http.Server/Overlapped/ThreadPoolBoundHandle.cs b/src/Microsoft.Net.Http.Server/Overlapped/ThreadPoolBoundHandle.cs
index 595d347a57..4356a57f7a 100644
--- a/src/Microsoft.Net.Http.Server/Overlapped/ThreadPoolBoundHandle.cs
+++ b/src/Microsoft.Net.Http.Server/Overlapped/ThreadPoolBoundHandle.cs
@@ -1,4 +1,4 @@
-#if !DOTNET5_4 // TODO: Temp copy. Remove once we target net46.
+#if !NETSTANDARD1_3 // TODO: Temp copy. Remove once we target net46.
 using System;
 using System.Runtime.InteropServices;
 namespace System.Threading
diff --git a/src/Microsoft.Net.Http.Server/Overlapped/ThreadPoolBoundHandleOverlapped.cs b/src/Microsoft.Net.Http.Server/Overlapped/ThreadPoolBoundHandleOverlapped.cs
index 753ee35ffd..55e5458f04 100644
--- a/src/Microsoft.Net.Http.Server/Overlapped/ThreadPoolBoundHandleOverlapped.cs
+++ b/src/Microsoft.Net.Http.Server/Overlapped/ThreadPoolBoundHandleOverlapped.cs
@@ -1,4 +1,4 @@
-#if !DOTNET5_4 // TODO: Temp copy. Remove once we target net46.
+#if !NETSTANDARD1_3 // TODO: Temp copy. Remove once we target net46.
 using System;
 namespace System.Threading
 {
diff --git a/src/Microsoft.Net.Http.Server/RequestProcessing/OpaqueStream.cs b/src/Microsoft.Net.Http.Server/RequestProcessing/OpaqueStream.cs
index 4889a8c41b..6de4a8b38d 100644
--- a/src/Microsoft.Net.Http.Server/RequestProcessing/OpaqueStream.cs
+++ b/src/Microsoft.Net.Http.Server/RequestProcessing/OpaqueStream.cs
@@ -109,7 +109,7 @@ namespace Microsoft.Net.Http.Server
         {
             return _requestStream.ReadByte();
         }
-#if !DOTNET5_4
+#if !NETSTANDARD1_3
         public override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
         {
             return _requestStream.BeginRead(buffer, offset, count, callback, state);
@@ -143,7 +143,7 @@ namespace Microsoft.Net.Http.Server
         {
             _responseStream.WriteByte(value);
         }
-#if !DOTNET5_4
+#if !NETSTANDARD1_3
         public override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
         {
             return _responseStream.BeginWrite(buffer, offset, count, callback, state);
diff --git a/src/Microsoft.Net.Http.Server/RequestProcessing/RequestStream.cs b/src/Microsoft.Net.Http.Server/RequestProcessing/RequestStream.cs
index 162c8d683e..059dfe6822 100644
--- a/src/Microsoft.Net.Http.Server/RequestProcessing/RequestStream.cs
+++ b/src/Microsoft.Net.Http.Server/RequestProcessing/RequestStream.cs
@@ -203,7 +203,7 @@ namespace Microsoft.Net.Http.Server
             }
         }
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
         public unsafe IAsyncResult BeginRead(byte[] buffer, int offset, int size, AsyncCallback callback, object state)
 #else
         public override unsafe IAsyncResult BeginRead(byte[] buffer, int offset, int size, AsyncCallback callback, object state)
@@ -293,7 +293,7 @@ namespace Microsoft.Net.Http.Server
             return asyncResult;
         }
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
         public int EndRead(IAsyncResult asyncResult)
 #else
         public override int EndRead(IAsyncResult asyncResult)
@@ -428,7 +428,7 @@ namespace Microsoft.Net.Http.Server
             throw new InvalidOperationException(Resources.Exception_ReadOnlyStream);
         }
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
         public IAsyncResult BeginWrite(byte[] buffer, int offset, int size, AsyncCallback callback, object state)
 #else
         public override IAsyncResult BeginWrite(byte[] buffer, int offset, int size, AsyncCallback callback, object state)
@@ -437,7 +437,7 @@ namespace Microsoft.Net.Http.Server
             throw new InvalidOperationException(Resources.Exception_ReadOnlyStream);
         }
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
         public void EndWrite(IAsyncResult asyncResult)
 #else
         public override void EndWrite(IAsyncResult asyncResult)
diff --git a/src/Microsoft.Net.Http.Server/RequestProcessing/ResponseStream.cs b/src/Microsoft.Net.Http.Server/RequestProcessing/ResponseStream.cs
index 579dd1bbe2..fc0919602b 100644
--- a/src/Microsoft.Net.Http.Server/RequestProcessing/ResponseStream.cs
+++ b/src/Microsoft.Net.Http.Server/RequestProcessing/ResponseStream.cs
@@ -379,7 +379,7 @@ namespace Microsoft.Net.Http.Server
             throw new InvalidOperationException(Resources.Exception_WriteOnlyStream);
         }
 
-#if !DOTNET5_4
+#if !NETSTANDARD1_3
         public override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
         {
             throw new InvalidOperationException(Resources.Exception_WriteOnlyStream);
@@ -468,7 +468,7 @@ namespace Microsoft.Net.Http.Server
             }
         }
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
         public unsafe IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
 #else
         public override unsafe IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
@@ -476,7 +476,7 @@ namespace Microsoft.Net.Http.Server
         {
             return WriteAsync(buffer, offset, count).ToIAsyncResult(callback, state);
         }
-#if DOTNET5_4
+#if NETSTANDARD1_3
         public void EndWrite(IAsyncResult asyncResult)
 #else
         public override void EndWrite(IAsyncResult asyncResult)
diff --git a/src/Microsoft.Net.Http.Server/RequestProcessing/ResponseStreamAsyncResult.cs b/src/Microsoft.Net.Http.Server/RequestProcessing/ResponseStreamAsyncResult.cs
index 43e9b6c027..dbb9f9e557 100644
--- a/src/Microsoft.Net.Http.Server/RequestProcessing/ResponseStreamAsyncResult.cs
+++ b/src/Microsoft.Net.Http.Server/RequestProcessing/ResponseStreamAsyncResult.cs
@@ -120,7 +120,7 @@ namespace Microsoft.Net.Http.Server
             var boundHandle = responseStream.RequestContext.Server.BoundHandle;
 
             int bufferSize = 1024 * 64; // TODO: Validate buffer size choice.
-#if DOTNET5_4
+#if NETSTANDARD1_3
             _fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite, bufferSize /*, useAsync: true*/); // Extremely expensive.
 #else
             // It's too expensive to validate anything before opening the file. Open the file and then check the lengths.
diff --git a/src/Microsoft.Net.Http.Server/WebListenerException.cs b/src/Microsoft.Net.Http.Server/WebListenerException.cs
index 8920b3fd25..3c0cb7bb89 100644
--- a/src/Microsoft.Net.Http.Server/WebListenerException.cs
+++ b/src/Microsoft.Net.Http.Server/WebListenerException.cs
@@ -45,7 +45,7 @@ namespace Microsoft.Net.Http.Server
             : base(errorCode, message)
         {
         }
-#if DOTNET5_4
+#if NETSTANDARD1_3
         public int ErrorCode
 #else
         // the base class returns the HResult with this property
diff --git a/src/Microsoft.Net.Http.Server/fx/Microsoft/Win32/SafeHandles/CriticalHandleZeroOrMinusOneIsInvalid.cs b/src/Microsoft.Net.Http.Server/fx/Microsoft/Win32/SafeHandles/CriticalHandleZeroOrMinusOneIsInvalid.cs
index 4a310df3bf..5b29a3bc4c 100644
--- a/src/Microsoft.Net.Http.Server/fx/Microsoft/Win32/SafeHandles/CriticalHandleZeroOrMinusOneIsInvalid.cs
+++ b/src/Microsoft.Net.Http.Server/fx/Microsoft/Win32/SafeHandles/CriticalHandleZeroOrMinusOneIsInvalid.cs
@@ -21,7 +21,7 @@
 // 
 // ==--==
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
 
 namespace Microsoft.Win32.SafeHandles
 {
diff --git a/src/Microsoft.Net.Http.Server/fx/Microsoft/Win32/SafeHandles/SafeHandleZeroOrMinusOneIsInvalid.cs b/src/Microsoft.Net.Http.Server/fx/Microsoft/Win32/SafeHandles/SafeHandleZeroOrMinusOneIsInvalid.cs
index 650cffcf86..aef2c8b323 100644
--- a/src/Microsoft.Net.Http.Server/fx/Microsoft/Win32/SafeHandles/SafeHandleZeroOrMinusOneIsInvalid.cs
+++ b/src/Microsoft.Net.Http.Server/fx/Microsoft/Win32/SafeHandles/SafeHandleZeroOrMinusOneIsInvalid.cs
@@ -21,7 +21,7 @@
 // 
 // ==--==
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
 
 namespace Microsoft.Win32.SafeHandles
 {
diff --git a/src/Microsoft.Net.Http.Server/fx/System/Diagnostics/TraceEventType.cs b/src/Microsoft.Net.Http.Server/fx/System/Diagnostics/TraceEventType.cs
index bb8a238cf1..89ded72c3a 100644
--- a/src/Microsoft.Net.Http.Server/fx/System/Diagnostics/TraceEventType.cs
+++ b/src/Microsoft.Net.Http.Server/fx/System/Diagnostics/TraceEventType.cs
@@ -21,7 +21,7 @@
 // </copyright>
 //------------------------------------------------------------------------------
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
 
 using System;
 using System.ComponentModel;
diff --git a/src/Microsoft.Net.Http.Server/fx/System/ExternDll.cs b/src/Microsoft.Net.Http.Server/fx/System/ExternDll.cs
index 0aa12a91e5..989211c70c 100644
--- a/src/Microsoft.Net.Http.Server/fx/System/ExternDll.cs
+++ b/src/Microsoft.Net.Http.Server/fx/System/ExternDll.cs
@@ -21,7 +21,7 @@
 // </copyright>                                                                
 //------------------------------------------------------------------------------
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
 
 namespace System
 {
diff --git a/src/Microsoft.Net.Http.Server/fx/System/Runtime/InteropServices/ExternalException.cs b/src/Microsoft.Net.Http.Server/fx/System/Runtime/InteropServices/ExternalException.cs
index 1d6c825a65..807bdd2a60 100644
--- a/src/Microsoft.Net.Http.Server/fx/System/Runtime/InteropServices/ExternalException.cs
+++ b/src/Microsoft.Net.Http.Server/fx/System/Runtime/InteropServices/ExternalException.cs
@@ -31,7 +31,7 @@
 **
 =============================================================================*/
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
 
 namespace System.Runtime.InteropServices
 {
diff --git a/src/Microsoft.Net.Http.Server/fx/System/SafeNativeMethods.cs b/src/Microsoft.Net.Http.Server/fx/System/SafeNativeMethods.cs
index d890c46b3f..27a17a745c 100644
--- a/src/Microsoft.Net.Http.Server/fx/System/SafeNativeMethods.cs
+++ b/src/Microsoft.Net.Http.Server/fx/System/SafeNativeMethods.cs
@@ -21,7 +21,7 @@
 // </copyright>                                                                
 //------------------------------------------------------------------------------
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
 using System.Runtime.InteropServices;
 using System.Text;
 
diff --git a/src/Microsoft.Net.Http.Server/project.json b/src/Microsoft.Net.Http.Server/project.json
index 5b5861dd58..8d12e7b336 100644
--- a/src/Microsoft.Net.Http.Server/project.json
+++ b/src/Microsoft.Net.Http.Server/project.json
@@ -9,12 +9,14 @@
     "allowUnsafe": true,
     "warningsAsErrors": true,
     "keyFile": "../../tools/Key.snk",
-    "nowarn": [ "CS1591" ],
+    "nowarn": [
+      "CS1591"
+    ],
     "xmlDoc": true
   },
   "frameworks": {
     "net451": {},
-    "dotnet5.4": {
+    "netstandard1.3": {
       "dependencies": {
         "Microsoft.Win32.Primitives": "4.0.1-*",
         "System.Diagnostics.Contracts": "4.0.1-*",
@@ -29,7 +31,10 @@
         "System.Security.Principal.Windows": "4.0.0-*",
         "System.Text.Encoding.Extensions": "4.0.11-*",
         "System.Threading.Overlapped": "4.0.1-*"
-      }
+      },
+      "imports": [
+        "dotnet5.4"
+      ]
     }
   }
 }
\ No newline at end of file
diff --git a/src/Microsoft.Net.WebSockets.Server/NativeInterop/UnsafeNativeMethods.cs b/src/Microsoft.Net.WebSockets.Server/NativeInterop/UnsafeNativeMethods.cs
index 8b81c7cd96..43c86e1fa2 100644
--- a/src/Microsoft.Net.WebSockets.Server/NativeInterop/UnsafeNativeMethods.cs
+++ b/src/Microsoft.Net.WebSockets.Server/NativeInterop/UnsafeNativeMethods.cs
@@ -31,7 +31,7 @@ namespace Microsoft.Net.WebSockets
 {
     internal static class UnsafeNativeMethods
     {
-#if DOTNET5_4
+#if NETSTANDARD1_3
         private const string api_ms_win_core_libraryloader_LIB = "api-ms-win-core-libraryloader-l1-1-0.dll";
 #else    
         private const string KERNEL32 = "kernel32.dll";
@@ -40,14 +40,14 @@ namespace Microsoft.Net.WebSockets
 
         internal static class SafeNetHandles
         {
-#if DOTNET5_4
+#if NETSTANDARD1_3
             [DllImport(api_ms_win_core_libraryloader_LIB, ExactSpelling = true, CharSet = CharSet.Unicode, SetLastError = true)]
 #else
             [DllImport(KERNEL32, ExactSpelling = true, CharSet=CharSet.Unicode, SetLastError = true)]
 #endif
             internal static extern unsafe SafeLoadLibrary LoadLibraryExW([In] string lpwLibFileName, [In] void* hFile, [In] uint dwFlags);
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
             [DllImport(api_ms_win_core_libraryloader_LIB, ExactSpelling = true, SetLastError = true)]
 #else
             [DllImport(KERNEL32, ExactSpelling = true, SetLastError = true)]
@@ -173,7 +173,7 @@ namespace Microsoft.Net.WebSockets
 
             static WebSocketProtocolComponent()
             {
-#if DOTNET5_4
+#if NETSTANDARD1_3
                 DllFileName = Path.Combine(Environment.GetEnvironmentVariable("SYSTEMROOT"), "System32", WEBSOCKET);
 #else
                 DllFileName = Path.Combine(Environment.SystemDirectory, WEBSOCKET);
diff --git a/src/Microsoft.Net.WebSockets.Server/WebSocketBase.cs b/src/Microsoft.Net.WebSockets.Server/WebSocketBase.cs
index 6629e35271..1526acd056 100644
--- a/src/Microsoft.Net.WebSockets.Server/WebSocketBase.cs
+++ b/src/Microsoft.Net.WebSockets.Server/WebSocketBase.cs
@@ -1103,7 +1103,7 @@ namespace Microsoft.Net.WebSockets
 
             if (thisLockTaken || sessionHandleLockTaken)
             {
-#if !DOTNET5_4
+#if !NETSTANDARD1_3
                 RuntimeHelpers.PrepareConstrainedRegions();
 #endif
                 try
@@ -1189,7 +1189,7 @@ namespace Microsoft.Net.WebSockets
             Contract.Assert(lockObject != null, "'lockObject' MUST NOT be NULL.");
             if (lockTaken)
             {
-#if !DOTNET5_4
+#if !NETSTANDARD1_3
                 RuntimeHelpers.PrepareConstrainedRegions();
 #endif
                 try
@@ -2253,7 +2253,7 @@ namespace Microsoft.Net.WebSockets
                         "'webSocket.m_KeepAliveTracker' MUST NOT be NULL at this point.");
                     int keepAliveIntervalMilliseconds = (int)_keepAliveInterval.TotalMilliseconds;
                     Contract.Assert(keepAliveIntervalMilliseconds > 0, "'keepAliveIntervalMilliseconds' MUST be POSITIVE.");
-#if DOTNET5_4
+#if NETSTANDARD1_3
                     _keepAliveTimer = new Timer(_keepAliveTimerElapsedCallback, webSocket, keepAliveIntervalMilliseconds, Timeout.Infinite);
 #else
                     if (ExecutionContext.IsFlowSuppressed())
diff --git a/src/Microsoft.Net.WebSockets.Server/WebSocketException.cs b/src/Microsoft.Net.WebSockets.Server/WebSocketException.cs
index 0ae7e4bb89..a906a5d6aa 100644
--- a/src/Microsoft.Net.WebSockets.Server/WebSocketException.cs
+++ b/src/Microsoft.Net.WebSockets.Server/WebSocketException.cs
@@ -28,7 +28,7 @@ using System.Runtime.InteropServices;
 
 namespace Microsoft.Net.WebSockets
 {
-#if !DOTNET5_4
+#if !NETSTANDARD1_3
     [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2237:MarkISerializableTypesWithSerializable")]
 #endif
     internal sealed class WebSocketException : Win32Exception
@@ -115,7 +115,7 @@ namespace Microsoft.Net.WebSockets
             : base(message, innerException)
         { 
         }
-#if !DOTNET5_4
+#if !NETSTANDARD1_3
         public override int ErrorCode
         {
             get
diff --git a/src/Microsoft.Net.WebSockets.Server/fx/Microsoft/Win32/SafeHandles/SafeHandleZeroOrMinusOneIsInvalid.cs b/src/Microsoft.Net.WebSockets.Server/fx/Microsoft/Win32/SafeHandles/SafeHandleZeroOrMinusOneIsInvalid.cs
index 650cffcf86..aef2c8b323 100644
--- a/src/Microsoft.Net.WebSockets.Server/fx/Microsoft/Win32/SafeHandles/SafeHandleZeroOrMinusOneIsInvalid.cs
+++ b/src/Microsoft.Net.WebSockets.Server/fx/Microsoft/Win32/SafeHandles/SafeHandleZeroOrMinusOneIsInvalid.cs
@@ -21,7 +21,7 @@
 // 
 // ==--==
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
 
 namespace Microsoft.Win32.SafeHandles
 {
diff --git a/src/Microsoft.Net.WebSockets.Server/fx/System/AccessViolationException.cs b/src/Microsoft.Net.WebSockets.Server/fx/System/AccessViolationException.cs
index b7f6eb4071..0345bbc1a1 100644
--- a/src/Microsoft.Net.WebSockets.Server/fx/System/AccessViolationException.cs
+++ b/src/Microsoft.Net.WebSockets.Server/fx/System/AccessViolationException.cs
@@ -15,7 +15,7 @@
 // See the Apache 2 License for the specific language governing
 // permissions and limitations under the License.
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
 
 using System;
 using System.Collections.Generic;
diff --git a/src/Microsoft.Net.WebSockets.Server/fx/System/ExternDll.cs b/src/Microsoft.Net.WebSockets.Server/fx/System/ExternDll.cs
index 0aa12a91e5..989211c70c 100644
--- a/src/Microsoft.Net.WebSockets.Server/fx/System/ExternDll.cs
+++ b/src/Microsoft.Net.WebSockets.Server/fx/System/ExternDll.cs
@@ -21,7 +21,7 @@
 // </copyright>                                                                
 //------------------------------------------------------------------------------
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
 
 namespace System
 {
diff --git a/src/Microsoft.Net.WebSockets.Server/fx/System/Runtime/InteropServices/ExternalException.cs b/src/Microsoft.Net.WebSockets.Server/fx/System/Runtime/InteropServices/ExternalException.cs
index 1d6c825a65..807bdd2a60 100644
--- a/src/Microsoft.Net.WebSockets.Server/fx/System/Runtime/InteropServices/ExternalException.cs
+++ b/src/Microsoft.Net.WebSockets.Server/fx/System/Runtime/InteropServices/ExternalException.cs
@@ -31,7 +31,7 @@
 **
 =============================================================================*/
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
 
 namespace System.Runtime.InteropServices
 {
diff --git a/src/Microsoft.Net.WebSockets.Server/fx/System/SafeNativeMethods.cs b/src/Microsoft.Net.WebSockets.Server/fx/System/SafeNativeMethods.cs
index d890c46b3f..27a17a745c 100644
--- a/src/Microsoft.Net.WebSockets.Server/fx/System/SafeNativeMethods.cs
+++ b/src/Microsoft.Net.WebSockets.Server/fx/System/SafeNativeMethods.cs
@@ -21,7 +21,7 @@
 // </copyright>                                                                
 //------------------------------------------------------------------------------
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
 using System.Runtime.InteropServices;
 using System.Text;
 
diff --git a/src/Microsoft.Net.WebSockets.Server/fx/System/SystemException.cs b/src/Microsoft.Net.WebSockets.Server/fx/System/SystemException.cs
index 023d53ffc9..3b4436eb4e 100644
--- a/src/Microsoft.Net.WebSockets.Server/fx/System/SystemException.cs
+++ b/src/Microsoft.Net.WebSockets.Server/fx/System/SystemException.cs
@@ -15,7 +15,7 @@
 // See the Apache 2 License for the specific language governing
 // permissions and limitations under the License.
 
-#if DOTNET5_4
+#if NETSTANDARD1_3
 
 using System;
 using System.Collections.Generic;
diff --git a/src/Microsoft.Net.WebSockets.Server/project.json b/src/Microsoft.Net.WebSockets.Server/project.json
index 7d83e64239..11497df423 100644
--- a/src/Microsoft.Net.WebSockets.Server/project.json
+++ b/src/Microsoft.Net.WebSockets.Server/project.json
@@ -8,12 +8,14 @@
     "allowUnsafe": true,
     "warningsAsErrors": true,
     "keyFile": "../../tools/Key.snk",
-    "nowarn": [ "CS1591" ],
+    "nowarn": [
+      "CS1591"
+    ],
     "xmlDoc": true
   },
   "frameworks": {
     "net451": {},
-    "dotnet5.4": {
+    "netstandard1.3": {
       "dependencies": {
         "System.Collections": "4.0.11-*",
         "System.Linq": "4.1.0-*",
@@ -25,7 +27,10 @@
         "System.Threading.Tasks": "4.0.11-*",
         "System.Threading.Timer": "4.0.1-*",
         "System.Threading.ThreadPool": "4.0.10-*"
-      }
+      },
+      "imports": [
+        "dotnet5.4"
+      ]
     }
   }
 }
\ No newline at end of file
diff --git a/test/Microsoft.AspNetCore.Server.WebListener.FunctionalTests/RequestBodyTests.cs b/test/Microsoft.AspNetCore.Server.WebListener.FunctionalTests/RequestBodyTests.cs
index f11949a4e7..12944d9b8a 100644
--- a/test/Microsoft.AspNetCore.Server.WebListener.FunctionalTests/RequestBodyTests.cs
+++ b/test/Microsoft.AspNetCore.Server.WebListener.FunctionalTests/RequestBodyTests.cs
@@ -65,7 +65,7 @@ namespace Microsoft.AspNetCore.Server.WebListener
                 Assert.Equal("Hello World", response);
             }
         }
-#if !DNXCORE50
+#if !NETSTANDARDAPP1_5
         [Fact]
         public async Task RequestBody_ReadBeginEnd_Success()
         {
diff --git a/test/Microsoft.AspNetCore.Server.WebListener.FunctionalTests/ResponseHeaderTests.cs b/test/Microsoft.AspNetCore.Server.WebListener.FunctionalTests/ResponseHeaderTests.cs
index 4ec53b2a36..7242b3d17c 100644
--- a/test/Microsoft.AspNetCore.Server.WebListener.FunctionalTests/ResponseHeaderTests.cs
+++ b/test/Microsoft.AspNetCore.Server.WebListener.FunctionalTests/ResponseHeaderTests.cs
@@ -94,7 +94,7 @@ namespace Microsoft.AspNetCore.Server.WebListener
                 Assert.Equal(0, response.ContentLength);
                 Assert.NotNull(response.Headers["Date"]);
                 Assert.Equal("Microsoft-HTTPAPI/2.0", response.Headers["Server"]);
-#if DNXCORE50 // WebHeaderCollection.GetValues() not available in CoreCLR.
+#if NETSTANDARDAPP1_5 // WebHeaderCollection.GetValues() not available in CoreCLR.
                 Assert.Equal("custom1, and custom2, custom3", response.Headers["WWW-Authenticate"]);
 #else
                 Assert.Equal(new string[] { "custom1, and custom2", "custom3" }, response.Headers.GetValues("WWW-Authenticate"));
@@ -122,7 +122,7 @@ namespace Microsoft.AspNetCore.Server.WebListener
                 Assert.Equal(0, response.ContentLength);
                 Assert.NotNull(response.Headers["Date"]);
                 Assert.Equal("Microsoft-HTTPAPI/2.0", response.Headers["Server"]);
-#if DNXCORE50 // WebHeaderCollection.GetValues() not available in CoreCLR.
+#if NETSTANDARDAPP1_5 // WebHeaderCollection.GetValues() not available in CoreCLR.
                 Assert.Equal("custom1, and custom2, custom3", response.Headers["Custom-Header1"]);
 #else
                 Assert.Equal(new string[] { "custom1, and custom2", "custom3" }, response.Headers.GetValues("Custom-Header1"));
diff --git a/test/Microsoft.AspNetCore.Server.WebListener.FunctionalTests/project.json b/test/Microsoft.AspNetCore.Server.WebListener.FunctionalTests/project.json
index 001a9e016a..3d671edbdf 100644
--- a/test/Microsoft.AspNetCore.Server.WebListener.FunctionalTests/project.json
+++ b/test/Microsoft.AspNetCore.Server.WebListener.FunctionalTests/project.json
@@ -7,14 +7,17 @@
     "xunit": "2.1.0"
   },
   "frameworks": {
-    "dnxcore50": {
+    "netstandardapp1.5": {
       "dependencies": {
         "System.Net.Http.WinHttpHandler": "4.0.0-*",
         "System.Net.Requests": "4.0.11-*",
         "System.Net.WebHeaderCollection": "4.0.1-*",
         "dotnet-test-xunit": "1.0.0-dev-*"
       },
-      "imports": "portable-net451+win8"
+      "imports": [
+        "dnxcore50",
+        "portable-net451+win8"
+      ]
     },
     "net451": {
       "frameworkAssemblies": {
@@ -27,4 +30,4 @@
       }
     }
   }
-}
+}
\ No newline at end of file
diff --git a/test/Microsoft.Net.Http.Server.FunctionalTests/ResponseBodyTests.cs b/test/Microsoft.Net.Http.Server.FunctionalTests/ResponseBodyTests.cs
index 39dc2adcbc..3b195b2fc2 100644
--- a/test/Microsoft.Net.Http.Server.FunctionalTests/ResponseBodyTests.cs
+++ b/test/Microsoft.Net.Http.Server.FunctionalTests/ResponseBodyTests.cs
@@ -153,7 +153,7 @@ namespace Microsoft.Net.Http.Server
                 var context = await server.GetContextAsync();
                 context.Response.Headers["Content-lenGth"] = " 20 ";
                 context.Dispose();
-#if !DNXCORE50
+#if !NETSTANDARDAPP1_5
                 // HttpClient retries the request because it didn't get a response.
                 context = await server.GetContextAsync();
                 context.Response.Headers["Content-lenGth"] = " 20 ";
@@ -175,7 +175,7 @@ namespace Microsoft.Net.Http.Server
                 context.Response.Headers["Content-lenGth"] = " 20 ";
                 context.Response.Body.Write(new byte[5], 0, 5);
                 context.Dispose();
-#if !DNXCORE50
+#if !NETSTANDARDAPP1_5
                 // HttpClient retries the request because it didn't get a response.
                 context = await server.GetContextAsync();
                 context.Response.Headers["Content-lenGth"] = " 20 ";
@@ -199,7 +199,7 @@ namespace Microsoft.Net.Http.Server
                 context.Response.Body.Write(new byte[5], 0, 5);
                 Assert.Throws<InvalidOperationException>(() => context.Response.Body.Write(new byte[6], 0, 6));
                 context.Dispose();
-#if !DNXCORE50
+#if !NETSTANDARDAPP1_5
                 // HttpClient retries the request because it didn't get a response.
                 context = await server.GetContextAsync();
                 context.Response.Headers["Content-lenGth"] = " 10 ";
diff --git a/test/Microsoft.Net.Http.Server.FunctionalTests/ResponseHeaderTests.cs b/test/Microsoft.Net.Http.Server.FunctionalTests/ResponseHeaderTests.cs
index ffaa2442d6..a3c29a0991 100644
--- a/test/Microsoft.Net.Http.Server.FunctionalTests/ResponseHeaderTests.cs
+++ b/test/Microsoft.Net.Http.Server.FunctionalTests/ResponseHeaderTests.cs
@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
 
 using System;
 using System.Linq;
@@ -217,7 +217,7 @@ namespace Microsoft.Net.Http.Server
                 Assert.Equal(0, response.ContentLength);
                 Assert.NotNull(response.Headers["Date"]);
                 Assert.Equal("Microsoft-HTTPAPI/2.0", response.Headers["Server"]);
-#if DNXCORE50 // WebHeaderCollection.GetValues() not available in CoreCLR.
+#if NETSTANDARDAPP1_5 // WebHeaderCollection.GetValues() not available in CoreCLR.
                 Assert.Equal("custom1, and custom2, custom3", response.Headers["WWW-Authenticate"]);
 #else
                 Assert.Equal(new string[] { "custom1, and custom2", "custom3" }, response.Headers.GetValues("WWW-Authenticate"));
@@ -246,7 +246,7 @@ namespace Microsoft.Net.Http.Server
                 Assert.Equal(0, response.ContentLength);
                 Assert.NotNull(response.Headers["Date"]);
                 Assert.Equal("Microsoft-HTTPAPI/2.0", response.Headers["Server"]);
-#if DNXCORE50 // WebHeaderCollection.GetValues() not available in CoreCLR.
+#if NETSTANDARDAPP1_5 // WebHeaderCollection.GetValues() not available in CoreCLR.
                 Assert.Equal("custom1, and custom2, custom3", response.Headers["Custom-Header1"]);
 #else
                 Assert.Equal(new string[] { "custom1, and custom2", "custom3" }, response.Headers.GetValues("Custom-Header1"));
diff --git a/test/Microsoft.Net.Http.Server.FunctionalTests/ServerTests.cs b/test/Microsoft.Net.Http.Server.FunctionalTests/ServerTests.cs
index 9de25a8e0c..c1d87dfc0c 100644
--- a/test/Microsoft.Net.Http.Server.FunctionalTests/ServerTests.cs
+++ b/test/Microsoft.Net.Http.Server.FunctionalTests/ServerTests.cs
@@ -123,7 +123,7 @@ namespace Microsoft.Net.Http.Server
                 context.Abort();
                 Assert.True(canceled.WaitOne(interval), "Aborted");
                 Assert.True(ct.IsCancellationRequested, "IsCancellationRequested");
-#if !DNXCORE50
+#if !NETSTANDARDAPP1_5
                 // HttpClient re-tries the request because it doesn't know if the request was received.
                 context = await server.GetContextAsync();
                 context.Abort();
diff --git a/test/Microsoft.Net.Http.Server.FunctionalTests/project.json b/test/Microsoft.Net.Http.Server.FunctionalTests/project.json
index 1abe854726..c5dd6a27b7 100644
--- a/test/Microsoft.Net.Http.Server.FunctionalTests/project.json
+++ b/test/Microsoft.Net.Http.Server.FunctionalTests/project.json
@@ -8,7 +8,7 @@
     "xunit": "2.1.0"
   },
   "frameworks": {
-    "dnxcore50": {
+    "netstandardapp1.5": {
       "dependencies": {
         "System.Net.Http": "4.0.1-*",
         "System.Net.Http.WinHttpHandler": "4.0.0-*",
@@ -16,7 +16,10 @@
         "System.Net.WebSockets.Client": "4.0.0-*",
         "dotnet-test-xunit": "1.0.0-dev-*"
       },
-      "imports": "portable-net451+win8"
+      "imports": [
+        "dnxcore50",
+        "portable-net451+win8"
+      ]
     },
     "net451": {
       "frameworkAssemblies": {
@@ -31,4 +34,4 @@
       }
     }
   }
-}
+}
\ No newline at end of file