diff --git a/.travis.yml b/.travis.yml
index e57d7085..3543c8cd 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,10 +3,11 @@ mono: none
 sudo: required
 dist: trusty
 before_install:
-  - sudo sh -c 'echo "deb [arch=amd64] https://apt-mo.trafficmanager.net/repos/dotnet-release/ trusty main" > /etc/apt/sources.list.d/dotnetdev.list'
-  - sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 417A0893
+  - curl -O https://packages.microsoft.com/config/ubuntu/14.04/packages-microsoft-prod.deb
+  - sudo dpkg -i packages-microsoft-prod.deb
+  - sudo apt-get install apt-transport-https
   - sudo apt-get update
-  - sudo apt-get install dotnet-sdk-2.0.0
+  - sudo apt-get install dotnet-sdk-2.1
 services:
   - memcached  
 addons:
diff --git a/Enyim.Caching.Tests/Enyim.Caching.Tests.csproj b/Enyim.Caching.Tests/Enyim.Caching.Tests.csproj
index 77ce0f23..7f5c9d69 100644
--- a/Enyim.Caching.Tests/Enyim.Caching.Tests.csproj
+++ b/Enyim.Caching.Tests/Enyim.Caching.Tests.csproj
@@ -1,11 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>netcoreapp2.0</TargetFramework>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
     <IsPackable>false</IsPackable>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="2.0.0" />
-    <PackageReference Include="Microsoft.Extensions.Logging" Version="2.0.2" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="2.1.0" />
+    <PackageReference Include="Microsoft.Extensions.Logging" Version="2.1.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.7.2" />
     <PackageReference Include="xunit" Version="2.3.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.3.1" />
diff --git a/Enyim.Caching/Enyim.Caching.csproj b/Enyim.Caching/Enyim.Caching.csproj
index 45c2a1c6..28feb5ec 100755
--- a/Enyim.Caching/Enyim.Caching.csproj
+++ b/Enyim.Caching/Enyim.Caching.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <Description>EnyimMemcachedCore is a Memcached client library for .NET Core. Usage: Add services.AddEnyimMemcached(...) and app.UseEnyimMemcached() in Startup. Add IMemcachedClient into constructor.</Description>
-    <VersionPrefix>2.1.4</VersionPrefix>
+    <VersionPrefix>2.1.5</VersionPrefix>
     <Authors>cnblogs.com</Authors>
     <TargetFramework>netstandard2.0</TargetFramework>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
@@ -16,13 +16,13 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="2.0.2" />
-    <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="2.0.2" />
-    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="2.0.2" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="2.1.0" />
+    <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="2.1.0" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="2.1.0" />
     <PackageReference Include="Newtonsoft.Json" Version="11.0.2" />
-    <PackageReference Include="Microsoft.Extensions.Options" Version="2.0.2" />
-    <PackageReference Include="Microsoft.Extensions.Caching.Abstractions" Version="2.0.2" />
-    <PackageReference Include="Microsoft.AspNetCore.Http.Abstractions" Version="2.0.3" />
+    <PackageReference Include="Microsoft.Extensions.Options" Version="2.1.0" />
+    <PackageReference Include="Microsoft.Extensions.Caching.Abstractions" Version="2.1.0" />
+    <PackageReference Include="Microsoft.AspNetCore.Http.Abstractions" Version="2.1.0" />
     <PackageReference Include="Newtonsoft.Json.Bson" Version="1.0.1" />
   </ItemGroup>
 </Project>
diff --git a/MemcachedTest/MemcachedTest.csproj b/MemcachedTest/MemcachedTest.csproj
index 1baa5e22..530ae806 100755
--- a/MemcachedTest/MemcachedTest.csproj
+++ b/MemcachedTest/MemcachedTest.csproj
@@ -1,12 +1,12 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFramework>netcoreapp2.0</TargetFramework>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
     <IsPackable>false</IsPackable>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="2.0.0" />
-    <PackageReference Include="Microsoft.Extensions.Logging" Version="2.0.2" />
-    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="2.0.2" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="2.1.0" />
+    <PackageReference Include="Microsoft.Extensions.Logging" Version="2.1.0" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="2.1.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.7.2" />
     <PackageReference Include="xunit" Version="2.3.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.3.1" />
diff --git a/SampleWebApp/SampleWebApp.csproj b/SampleWebApp/SampleWebApp.csproj
index 2f60b431..0e63aa2c 100644
--- a/SampleWebApp/SampleWebApp.csproj
+++ b/SampleWebApp/SampleWebApp.csproj
@@ -1,12 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp2.0</TargetFramework>
-    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.8" />
+    <PackageReference Include="Microsoft.AspNetCore.All" Version="2.1.0" />
   </ItemGroup>
 
   <ItemGroup>