diff --git a/README.md b/README.md
index 849f556c6..31d0e4253 100644
--- a/README.md
+++ b/README.md
@@ -105,7 +105,7 @@ Note: the PSScriptAnalyzer Chocolatey package is provided and supported by the c
 
 #### Requirements
 
-* [.NET Core 2.1.401 SDK](https://www.microsoft.com/net/download/dotnet-core/2.1#sdk-2.1.401) or newer patch release
+* [.NET Core 2.1.502 SDK](https://www.microsoft.com/net/download/dotnet-core/2.1#sdk-2.1.502) or newer patch release
 * [PlatyPS 0.9.0 or greater](https://github.com/PowerShell/platyPS/releases)
 * Optionally but recommended for development: [Visual Studio 2017](https://www.visualstudio.com/downloads/)
 
diff --git a/Rules/Strings.Designer.cs b/Rules/Strings.Designer.cs
index ba1d61a4d..edb0a29f4 100644
--- a/Rules/Strings.Designer.cs
+++ b/Rules/Strings.Designer.cs
@@ -602,7 +602,7 @@ internal static string AvoidUsernameAndPasswordParamsError {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to AvoidUsingUserNameAndPassWordParams.
+        ///   Looks up a localized string similar to AvoidUsingUsernameAndPasswordParams.
         /// </summary>
         internal static string AvoidUsernameAndPasswordParamsName {
             get {
diff --git a/Rules/Strings.resx b/Rules/Strings.resx
index d4ebf259c..56cdb1794 100644
--- a/Rules/Strings.resx
+++ b/Rules/Strings.resx
@@ -484,7 +484,7 @@
     <value>Function '{0}' has both Username and Password parameters. Either set the type of the Password parameter to SecureString or replace the Username and Password parameters with a Credential parameter of type PSCredential. If using a Credential parameter in PowerShell 4.0 or earlier, please define a credential transformation attribute after the PSCredential type attribute.</value>
   </data>
   <data name="AvoidUsernameAndPasswordParamsName" xml:space="preserve">
-    <value>AvoidUsingUserNameAndPassWordParams</value>
+    <value>AvoidUsingUsernameAndPasswordParams</value>
   </data>
   <data name="AvoidInvokingEmptyMembersCommonName" xml:space="preserve">
     <value>Avoid Invoking Empty Members</value>
diff --git a/Rules/UseStandardDSCFunctionsInResource.cs b/Rules/UseStandardDSCFunctionsInResource.cs
index b93147bf7..7022da2d4 100644
--- a/Rules/UseStandardDSCFunctionsInResource.cs
+++ b/Rules/UseStandardDSCFunctionsInResource.cs
@@ -35,7 +35,7 @@ public IEnumerable<DiagnosticRecord> AnalyzeDSCResource(Ast ast, string fileName
             List<string> expectedTargetResourceFunctionNames = new List<string>(new string[]  { "Get-TargetResource", "Set-TargetResource", "Test-TargetResource" });
 
             // Retrieve a list of Asts where the function name contains TargetResource            
-            IEnumerable<Ast> functionDefinitionAsts = (ast.FindAll(dscAst => dscAst is FunctionDefinitionAst && ((dscAst as FunctionDefinitionAst).Name.IndexOf("targetResource", StringComparison.CurrentCultureIgnoreCase) != -1), true));
+            IEnumerable<Ast> functionDefinitionAsts = (ast.FindAll(dscAst => dscAst is FunctionDefinitionAst && ((dscAst as FunctionDefinitionAst).Name.IndexOf("targetResource", StringComparison.OrdinalIgnoreCase) != -1), true));
 
             List<string> targetResourceFunctionNamesInAst = new List<string>();
             foreach (FunctionDefinitionAst functionDefinitionAst in functionDefinitionAsts)
@@ -46,7 +46,7 @@ public IEnumerable<DiagnosticRecord> AnalyzeDSCResource(Ast ast, string fileName
             foreach (string expectedTargetResourceFunctionName in expectedTargetResourceFunctionNames)
             {
                 // If the Ast does not contain the expected functions, provide a Rule violation message
-                if (!targetResourceFunctionNamesInAst.Contains(expectedTargetResourceFunctionName, StringComparer.CurrentCultureIgnoreCase))
+                if (!targetResourceFunctionNamesInAst.Contains(expectedTargetResourceFunctionName, StringComparer.OrdinalIgnoreCase))
                 {
                     yield return new DiagnosticRecord(string.Format(CultureInfo.CurrentCulture, Strings.UseStandardDSCFunctionsInResourceError, expectedTargetResourceFunctionName),
                         ast.Extent, GetName(), DiagnosticSeverity.Error, fileName);      
diff --git a/global.json b/global.json
index 3520291b0..d328f8082 100644
--- a/global.json
+++ b/global.json
@@ -1,5 +1,5 @@
 {
     "sdk": {
-        "version": "2.1.401"
+        "version": "2.1.502"
     }
 }
diff --git a/tools/appveyor.psm1 b/tools/appveyor.psm1
index cc8e15f81..46fc0736a 100644
--- a/tools/appveyor.psm1
+++ b/tools/appveyor.psm1
@@ -32,13 +32,33 @@ function Invoke-AppVeyorInstall {
 
     # the legacy WMF4 image only has the old preview SDKs of dotnet
     $globalDotJson = Get-Content (Join-Path $PSScriptRoot '..\global.json') -Raw | ConvertFrom-Json
-    $dotNetCoreSDKVersion = $globalDotJson.sdk.version
-    # don't try to run this script on linux - we have to do the negative check because IsLinux will be defined in core, but not windows
-    if (-not ((dotnet --version).StartsWith($dotNetCoreSDKVersion)) -and ! $IsLinux ) {
-        [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12 # https://github.com/dotnet/announcements/issues/77
-        Invoke-WebRequest 'https://dot.net/v1/dotnet-install.ps1' -OutFile dotnet-install.ps1
-        .\dotnet-install.ps1 -Version $dotNetCoreSDKVersion
-        Remove-Item .\dotnet-install.ps1
+    $requiredDotNetCoreSDKVersion = $globalDotJson.sdk.version
+    if ($PSVersionTable.PSVersion.Major -gt 4) {
+        $requiredDotNetCoreSDKVersionPresent = (dotnet --list-sdks) -match $requiredDotNetCoreSDKVersion
+    }
+    else {
+        # WMF 4 image has old SDK that does not have --list-sdks parameter
+        $requiredDotNetCoreSDKVersionPresent = (dotnet --version).StartsWith($requiredDotNetCoreSDKVersion)
+    }
+    if (-not $requiredDotNetCoreSDKVersionPresent) {
+        Write-Verbose -Verbose "Installing required .Net CORE SDK $requiredDotNetCoreSDKVersion"
+        $originalSecurityProtocol = [Net.ServicePointManager]::SecurityProtocol
+        try {
+            [Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12
+            if ($IsLinux -or $isMacOS) {
+                Invoke-WebRequest 'https://dot.net/v1/dotnet-install.sh' -OutFile dotnet-install.sh
+                bash dotnet-install.sh --version $requiredDotNetCoreSDKVersion
+                [System.Environment]::SetEnvironmentVariable('PATH', "/home/appveyor/.dotnet$([System.IO.Path]::PathSeparator)$PATH")
+            }
+            else {
+                Invoke-WebRequest 'https://dot.net/v1/dotnet-install.ps1' -OutFile dotnet-install.ps1
+                .\dotnet-install.ps1 -Version $requiredDotNetCoreSDKVersion
+            }
+        }
+        finally {
+            [Net.ServicePointManager]::SecurityProtocol = $originalSecurityProtocol
+            Remove-Item .\dotnet-install.*
+        }
     }
 }