diff --git a/L3/K2/K2.csproj b/L3/K2/K2.csproj
index ab828a7..b2fabe7 100644
--- a/L3/K2/K2.csproj
+++ b/L3/K2/K2.csproj
@@ -2,7 +2,8 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
+    <LangVersion>7.1</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/L3/LD_24/LD_24.csproj b/L3/LD_24/LD_24.csproj
index 9d36916..5edc7b9 100644
--- a/L3/LD_24/LD_24.csproj
+++ b/L3/LD_24/LD_24.csproj
@@ -13,7 +13,7 @@
     <AppDesignerFolder>Properties</AppDesignerFolder>
     <RootNamespace>LD_24</RootNamespace>
     <AssemblyName>LD_24</AssemblyName>
-    <TargetFrameworkVersion>v4.6.1</TargetFrameworkVersion>
+    <TargetFrameworkVersion>v4.6</TargetFrameworkVersion>
     <UseIISExpress>true</UseIISExpress>
     <Use64BitIISExpress />
     <IISExpressSSLPort />
@@ -23,6 +23,7 @@
     <UseGlobalApplicationHostFile />
     <NuGetPackageImportStamp>
     </NuGetPackageImportStamp>
+    <TargetFrameworkProfile />
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <DebugSymbols>true</DebugSymbols>
@@ -32,6 +33,7 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
+    <LangVersion>7.1</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugSymbols>true</DebugSymbols>
@@ -41,15 +43,10 @@
     <DefineConstants>TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
+    <LangVersion>7.1</LangVersion>
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="Microsoft.CSharp" />
-    <Reference Include="System.Runtime.CompilerServices.Unsafe, Version=4.0.4.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <HintPath>..\packages\System.Runtime.CompilerServices.Unsafe.4.5.0\lib\netstandard2.0\System.Runtime.CompilerServices.Unsafe.dll</HintPath>
-    </Reference>
-    <Reference Include="System.Threading.Tasks.Extensions, Version=4.2.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51, processorArchitecture=MSIL">
-      <HintPath>..\packages\System.Threading.Tasks.Extensions.4.5.0\lib\netstandard2.0\System.Threading.Tasks.Extensions.dll</HintPath>
-    </Reference>
     <Reference Include="System.Web.DynamicData" />
     <Reference Include="System.Web.Entity" />
     <Reference Include="System.Web.ApplicationServices" />
diff --git a/L3/LD_24/Web.config b/L3/LD_24/Web.config
index 93be01c..2346027 100644
--- a/L3/LD_24/Web.config
+++ b/L3/LD_24/Web.config
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0"?>
 <!--
   For more information on how to configure your ASP.NET application, please visit
   https://go.microsoft.com/fwlink/?LinkId=169433
@@ -7,10 +7,18 @@
   <appSettings>
     <add key="ValidationSettings:UnobtrusiveValidationMode" value="None"/>
   </appSettings>
+  <!--
+    For a description of web.config changes see http://go.microsoft.com/fwlink/?LinkId=235367.
+
+    The following attributes can be set on the <httpRuntime> tag.
+      <system.Web>
+        <httpRuntime targetFramework="4.6" />
+      </system.Web>
+  -->
   <system.web>
-    <compilation debug="true" targetFramework="4.6.1"/>
-    <httpRuntime targetFramework="4.6.1"/>
-	<globalization fileEncoding="utf-8"/>
+    <compilation debug="true" targetFramework="4.6"/>
+    <httpRuntime targetFramework="4.6"/>
+    <globalization fileEncoding="utf-8"/>
   </system.web>
   <system.codedom>
     <compilers>
@@ -18,221 +26,220 @@
       <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:default /nowarn:41008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+"/>
     </compilers>
   </system.codedom>
-
-	<runtime>
-		<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
-			<dependentAssembly>
-				<assemblyIdentity name="System.Xml.XPath.XDocument" publicKeyToken="B03F5F7F11D50A3A" culture="neutral"/>
-				<bindingRedirect oldVersion="0.0.0.0-4.1.0.0" newVersion="4.1.0.0"/>
-			</dependentAssembly>
-			<dependentAssembly>
-				<assemblyIdentity name="System.Xml.XmlSerializer" publicKeyToken="B03F5F7F11D50A3A" culture="neutral"/>
-				<bindingRedirect oldVersion="0.0.0.0-4.0.11.0" newVersion="4.0.11.0"/>
-			</dependentAssembly>
-			<dependentAssembly>
-				<assemblyIdentity name="System.Xml.XDocument" publicKeyToken="B03F5F7F11D50A3A" culture="neutral"/>
-				<bindingRedirect oldVersion="0.0.0.0-4.0.11.0" newVersion="4.0.11.0"/>
-			</dependentAssembly>
-			<dependentAssembly>
-				<assemblyIdentity name="System.Xml.ReaderWriter" publicKeyToken="B03F5F7F11D50A3A" culture="neutral"/>
-				<bindingRedirect oldVersion="0.0.0.0-4.1.1.0" newVersion="4.1.1.0"/>
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-			<dependentAssembly>
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diff --git a/L3/LD_24/packages.config b/L3/LD_24/packages.config
index d6710b5..8dadb84 100644
--- a/L3/LD_24/packages.config
+++ b/L3/LD_24/packages.config
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
   <package id="Microsoft.CodeDom.Providers.DotNetCompilerPlatform" version="2.0.0" targetFramework="net461" />
-  <package id="System.Runtime.CompilerServices.Unsafe" version="4.5.0" targetFramework="net461" />
-  <package id="System.Threading.Tasks.Extensions" version="4.5.0" targetFramework="net461" />
+  <package id="System.Runtime.CompilerServices.Unsafe" version="4.5.0" targetFramework="net461" requireReinstallation="true" />
+  <package id="System.Threading.Tasks.Extensions" version="4.5.0" targetFramework="net461" requireReinstallation="true" />
 </packages>
\ No newline at end of file
diff --git a/L3/LD_24Tests/LD_24Tests.csproj b/L3/LD_24Tests/LD_24Tests.csproj
index b831153..7566a8d 100644
--- a/L3/LD_24Tests/LD_24Tests.csproj
+++ b/L3/LD_24Tests/LD_24Tests.csproj
@@ -1,14 +1,16 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
 
     <IsPackable>false</IsPackable>
+
+    <LangVersion>7.1</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>
     <PackageReference Include="Bogus" Version="34.0.1" />
-    <PackageReference Include="FluentAssertions" Version="6.6.0" />
+    <PackageReference Include="FluentAssertions" Version="5.10.3" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.5.0" />
     <PackageReference Include="xunit" Version="2.4.1" />
     <PackageReference Include="xunit.abstractions" Version="2.0.3" />