diff --git a/.paket/Paket.Restore.targets b/.paket/Paket.Restore.targets
index df16b3a..be250c8 100644
--- a/.paket/Paket.Restore.targets
+++ b/.paket/Paket.Restore.targets
@@ -5,6 +5,11 @@
     <!-- make MSBuild track this file for incremental builds. -->
     <!-- ref https://blogs.msdn.microsoft.com/msbuild/2005/09/26/how-to-ensure-changes-to-a-custom-target-file-prompt-a-rebuild/ -->
     <MSBuildAllProjects>$(MSBuildAllProjects);$(MSBuildThisFileFullPath)</MSBuildAllProjects>
+
+    <DetectedMSBuildVersion>$(MSBuildVersion)</DetectedMSBuildVersion>
+    <DetectedMSBuildVersion Condition="$(MSBuildVersion) == ''">15.0.0</DetectedMSBuildVersion>
+    <MSBuildSupportsHashing>false</MSBuildSupportsHashing>
+    <MSBuildSupportsHashing Condition=" '$(DetectedMSBuildVersion)' &gt; '15.8.0' ">true</MSBuildSupportsHashing>
     <!-- Mark that this target file has been loaded.  -->
     <IsPaketRestoreTargetsFileLoaded>true</IsPaketRestoreTargetsFileLoaded>
     <PaketToolsPath>$(MSBuildThisFileDirectory)</PaketToolsPath>
@@ -73,37 +78,47 @@
     <MSBuild Projects="$(PaketToolsPath)paket.bootstrapper.proj" Targets="Restore" />
   </Target>
 
+  <!-- Official workaround for https://docs.microsoft.com/en-us/visualstudio/msbuild/getfilehash-task?view=vs-2019 -->
+  <UsingTask TaskName="Microsoft.Build.Tasks.GetFileHash" AssemblyName="Microsoft.Build.Tasks.Core, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" Condition=" '$(MSBuildSupportsHashing)' == 'true' And '$(DetectedMSBuildVersion)' &lt; '16.0.360' " />
+  <UsingTask TaskName="Microsoft.Build.Tasks.VerifyFileHash" AssemblyName="Microsoft.Build.Tasks.Core, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" Condition=" '$(MSBuildSupportsHashing)' == 'true' And '$(DetectedMSBuildVersion)' &lt; '16.0.360' " />
   <Target Name="PaketRestore" Condition="'$(PaketRestoreDisabled)' != 'True'" BeforeTargets="_GenerateDotnetCliToolReferenceSpecs;_GenerateProjectRestoreGraphPerFramework;_GenerateRestoreGraphWalkPerFramework;CollectPackageReferences" DependsOnTargets="PaketBootstrapping">
 
-    <!-- Step 1 Check if lockfile is properly restored -->
+    <!-- Step 1 Check if lockfile is properly restored (if the hash of the lockfile and the cache-file match) -->
     <PropertyGroup>
       <PaketRestoreRequired>true</PaketRestoreRequired>
       <NoWarn>$(NoWarn);NU1603;NU1604;NU1605;NU1608</NoWarn>
+      <CacheFilesExist>false</CacheFilesExist>
+      <CacheFilesExist Condition=" Exists('$(PaketRestoreCacheFile)') And Exists('$(PaketLockFilePath)') ">true</CacheFilesExist>
     </PropertyGroup>
 
-    <!-- Because ReadAllText is slow on osx/linux, try to find shasum and awk -->
-    <PropertyGroup>
-      <PaketRestoreCachedHasher Condition="'$(OS)' != 'Windows_NT' And '$(PaketRestoreCachedHasher)' == '' And Exists('/usr/bin/shasum') And Exists('/usr/bin/awk')">/usr/bin/shasum "$(PaketRestoreCacheFile)" | /usr/bin/awk '{ print $1 }'</PaketRestoreCachedHasher>
-      <PaketRestoreLockFileHasher Condition="'$(OS)' != 'Windows_NT' And '$(PaketRestoreLockFileHash)' == '' And Exists('/usr/bin/shasum') And Exists('/usr/bin/awk')">/usr/bin/shasum "$(PaketLockFilePath)" | /usr/bin/awk '{ print $1 }'</PaketRestoreLockFileHasher>
+    <!-- Read the hash of the lockfile -->
+    <GetFileHash Condition=" '$(MSBuildSupportsHashing)' == 'true' And '$(CacheFilesExist)' == 'true' " Files="$(PaketLockFilePath)" Algorithm="SHA256" HashEncoding="hex" >
+      <Output TaskParameter="Hash" PropertyName="PaketRestoreLockFileHash" />
+    </GetFileHash>
+    <!-- Read the hash of the cache, which is json, but a very simple key value object -->
+    <PropertyGroup Condition=" '$(MSBuildSupportsHashing)' == 'true' And '$(CacheFilesExist)' == 'true' ">
+        <PaketRestoreCachedContents>$([System.IO.File]::ReadAllText('$(PaketRestoreCacheFile)'))</PaketRestoreCachedContents>
+    </PropertyGroup>
+    <ItemGroup Condition=" '$(MSBuildSupportsHashing)' == 'true' And '$(CacheFilesExist)' == 'true' ">
+        <!-- Parse our simple 'paket.restore.cached' json ...-->
+        <PaketRestoreCachedSplitObject Include="$([System.Text.RegularExpressions.Regex]::Split(`$(PaketRestoreCachedContents)`, `{|}|,`))"></PaketRestoreCachedSplitObject>
+        <!-- Keep Key, Value ItemGroup-->
+        <PaketRestoreCachedKeyValue Include="@(PaketRestoreCachedSplitObject)" 
+            Condition=" $([System.Text.RegularExpressions.Regex]::Split(`%(Identity)`, `&quot;: &quot;`).Length) &gt; 1 ">
+          <Key>$([System.Text.RegularExpressions.Regex]::Split(`%(Identity)`, `": "`)[0].Replace(`"`, ``).Replace(` `, ``))</Key>
+          <Value>$([System.Text.RegularExpressions.Regex]::Split(`%(Identity)`, `": "`)[1].Replace(`"`, ``).Replace(` `, ``))</Value>
+        </PaketRestoreCachedKeyValue>
+    </ItemGroup>
+    <PropertyGroup Condition=" '$(MSBuildSupportsHashing)' == 'true' And '$(CacheFilesExist)' == 'true' ">
+        <!-- Retrieve the hashes we are interested in -->
+        <PackagesDownloadedHash Condition=" '%(PaketRestoreCachedKeyValue.Key)' == 'packagesDownloadedHash' ">%(PaketRestoreCachedKeyValue.Value)</PackagesDownloadedHash>
+        <ProjectsRestoredHash Condition=" '%(PaketRestoreCachedKeyValue.Key)' == 'projectsRestoredHash' ">%(PaketRestoreCachedKeyValue.Value)</ProjectsRestoredHash>
     </PropertyGroup>
 
-    <!-- If shasum and awk exist get the hashes -->
-    <Exec StandardOutputImportance="Low" Condition=" '$(PaketRestoreCachedHasher)' != '' " Command="$(PaketRestoreCachedHasher)" ConsoleToMSBuild='true'>
-      <Output TaskParameter="ConsoleOutput" PropertyName="PaketRestoreCachedHash" />
-    </Exec>
-    <Exec StandardOutputImportance="Low" Condition=" '$(PaketRestoreLockFileHasher)' != '' " Command="$(PaketRestoreLockFileHasher)" ConsoleToMSBuild='true'>
-      <Output TaskParameter="ConsoleOutput" PropertyName="PaketRestoreLockFileHash" />
-    </Exec>
-
-    <!-- Debug whats going on -->
-    <Message Importance="low" Text="calling paket restore with targetframework=$(TargetFramework) targetframeworks=$(TargetFrameworks)" />
-
-    <PropertyGroup Condition="Exists('$(PaketRestoreCacheFile)') ">
-      <!-- if no hash has been done yet fall back to just reading in the files and comparing them -->
-      <PaketRestoreCachedHash Condition=" '$(PaketRestoreCachedHash)' == '' ">$([System.IO.File]::ReadAllText('$(PaketRestoreCacheFile)'))</PaketRestoreCachedHash>
-      <PaketRestoreLockFileHash Condition=" '$(PaketRestoreLockFileHash)' == '' ">$([System.IO.File]::ReadAllText('$(PaketLockFilePath)'))</PaketRestoreLockFileHash>
+    <PropertyGroup Condition=" '$(MSBuildSupportsHashing)' == 'true' And '$(CacheFilesExist)' == 'true' ">
+      <!-- If the restire file doesn't exist we need to restore, otherwise only if hashes don't match -->
       <PaketRestoreRequired>true</PaketRestoreRequired>
-      <PaketRestoreRequired Condition=" '$(PaketRestoreLockFileHash)' == '$(PaketRestoreCachedHash)' ">false</PaketRestoreRequired>
+      <PaketRestoreRequired Condition=" '$(PaketRestoreLockFileHash)' == '$(ProjectsRestoredHash)' ">false</PaketRestoreRequired>
       <PaketRestoreRequired Condition=" '$(PaketRestoreLockFileHash)' == '' ">true</PaketRestoreRequired>
     </PropertyGroup>
 
@@ -116,7 +131,10 @@
     </PropertyGroup>
 
     <!-- Do a global restore if required -->
+    <Warning Text="This version of MSBuild (we assume '$(DetectedMSBuildVersion)' or older) doesn't support GetFileHash, so paket fast restore is disabled." Condition=" '$(MSBuildSupportsHashing)' != 'true' " />
+    <Error Text="Stop build because of PAKET_ERROR_ON_MSBUILD_EXEC and we always call the bootstrapper" Condition=" '$(PAKET_ERROR_ON_MSBUILD_EXEC)' == 'true' AND '$(PaketBootstrapperStyle)' == 'classic' AND Exists('$(PaketBootStrapperExePath)') AND !(Exists('$(PaketExePath)'))" />
     <Exec Command='$(PaketBootStrapperCommand)' Condition=" '$(PaketBootstrapperStyle)' == 'classic' AND Exists('$(PaketBootStrapperExePath)') AND !(Exists('$(PaketExePath)'))" ContinueOnError="false" />
+    <Error Text="Stop build because of PAKET_ERROR_ON_MSBUILD_EXEC and we need a full restore (hashes don't match)" Condition=" '$(PAKET_ERROR_ON_MSBUILD_EXEC)' == 'true' AND '$(PaketRestoreRequired)' == 'true' AND '$(PaketDisableGlobalRestore)' != 'true'" />
     <Exec Command='$(PaketCommand) restore' Condition=" '$(PaketRestoreRequired)' == 'true' AND '$(PaketDisableGlobalRestore)' != 'true' " ContinueOnError="false" />
     
     <!-- Step 2 Detect project specific changes -->
@@ -126,7 +144,7 @@
       <MyTargetFrameworks Condition="'$(TargetFrameworks)' != '' AND '$(TargetFramework)' == '' " Include="$(TargetFrameworks)"></MyTargetFrameworks>
       <PaketResolvedFilePaths Include="@(MyTargetFrameworks -> '$(PaketIntermediateOutputPath)\$(MSBuildProjectFile).%(Identity).paket.resolved')"></PaketResolvedFilePaths>
     </ItemGroup>
-    <Message Importance="low" Text="MyTargetFrameworks=@(MyTargetFrameworks) PaketResolvedFilePaths=@(PaketResolvedFilePaths)" />
+
     <PropertyGroup>
       <PaketReferencesCachedFilePath>$(PaketIntermediateOutputPath)\$(MSBuildProjectFile).paket.references.cached</PaketReferencesCachedFilePath>
       <!-- MyProject.fsproj.paket.references has the highest precedence -->
@@ -163,6 +181,7 @@
 
     <!-- Step 3 Restore project specific stuff if required -->
     <Message Condition=" '$(PaketRestoreRequired)' == 'true' " Importance="low" Text="Detected a change ('$(PaketRestoreRequiredReason)') in the project file '$(MSBuildProjectFullPath)', calling paket restore" />
+    <Error Text="Stop build because of PAKET_ERROR_ON_MSBUILD_EXEC and we detected a change ('$(PaketRestoreRequiredReason)') in the project file '$(MSBuildProjectFullPath)'" Condition=" '$(PAKET_ERROR_ON_MSBUILD_EXEC)' == 'true' AND '$(PaketRestoreRequired)' == 'true' " />
     <Exec Command='$(PaketCommand) restore --project "$(MSBuildProjectFullPath)" --output-path "$(PaketIntermediateOutputPath)" --target-framework "$(TargetFrameworks)"' Condition=" '$(PaketRestoreRequired)' == 'true' AND '$(TargetFramework)' == '' " ContinueOnError="false" />
     <Exec Command='$(PaketCommand) restore --project "$(MSBuildProjectFullPath)" --output-path "$(PaketIntermediateOutputPath)" --target-framework "$(TargetFramework)"' Condition=" '$(PaketRestoreRequired)' == 'true' AND '$(TargetFramework)' != '' " ContinueOnError="false" />
 
@@ -224,8 +243,6 @@
   <Target Name="PaketDisableDirectPack" AfterTargets="_IntermediatePack" BeforeTargets="GenerateNuspec" Condition="('$(IsPackable)' == '' Or '$(IsPackable)' == 'true') And Exists('$(PaketIntermediateOutputPath)/$(MSBuildProjectFile).references')" >
     <PropertyGroup>
       <ContinuePackingAfterGeneratingNuspec>false</ContinuePackingAfterGeneratingNuspec>
-      <DetectedMSBuildVersion>$(MSBuildVersion)</DetectedMSBuildVersion>
-      <DetectedMSBuildVersion Condition="$(MSBuildVersion) == ''">15.8.0</DetectedMSBuildVersion>
     </PropertyGroup>
   </Target>
 
@@ -252,10 +269,12 @@
     </PropertyGroup>
 
     <ItemGroup>
-      <_NuspecFiles Include="$(AdjustedNuspecOutputPath)\*.$(PackageVersion).nuspec"/>
+      <_NuspecFiles Include="$(AdjustedNuspecOutputPath)\*.$(PackageVersion.Split(`+`)[0]).nuspec"/>
     </ItemGroup>
 
-    <Exec Command='$(PaketCommand) fix-nuspecs files "@(_NuspecFiles)" project-file "$(PaketProjectFile)" ' Condition="@(_NuspecFiles) != ''" />
+    <Error Text="Error Because of PAKET_ERROR_ON_MSBUILD_EXEC (not calling fix-nuspecs)" Condition=" '$(PAKET_ERROR_ON_MSBUILD_EXEC)' == 'true' " />
+    <Exec Condition="@(_NuspecFiles) != ''" Command='$(PaketCommand) fix-nuspecs files "@(_NuspecFiles)" project-file "$(PaketProjectFile)" ' />
+    <Error Condition="@(_NuspecFiles) == ''" Text='Could not find nuspec files in "$(AdjustedNuspecOutputPath)" (Version: "$(PackageVersion)"), therefore we cannot call "paket fix-nuspecs" and have to error out!' />
 
     <ConvertToAbsolutePath Condition="@(_NuspecFiles) != ''" Paths="@(_NuspecFiles)">
       <Output TaskParameter="AbsolutePaths" PropertyName="NuspecFileAbsolutePath" />
diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index 9c2fa59..965997e 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -1,6 +1,6 @@
 # Release Notes
 
-## 1.4.18 - 2019-07-28
+## 1.4.19 - 2019-07-28
 * Update deps
 * Use --self-contained for Firmware
 * Hook into view
diff --git a/src/PiServer/package.json b/src/PiServer/package.json
index 5b42c1c..932b433 100644
--- a/src/PiServer/package.json
+++ b/src/PiServer/package.json
@@ -1,6 +1,7 @@
 {
     "private": true,
     "dependencies": {
-        "mfrc522-rpi": "2.0.0"
+        "mfrc522-rpi": "2.0.0",
+        "rpi-softspi": "1.0.5"
     }
 }