diff --git a/MetaMorpheus/CMD/CMD.csproj b/MetaMorpheus/CMD/CMD.csproj
index f5b93d6ee..f278a13ce 100644
--- a/MetaMorpheus/CMD/CMD.csproj
+++ b/MetaMorpheus/CMD/CMD.csproj
@@ -24,7 +24,7 @@
     <PackageReference Include="Microsoft.ML.CpuMath" Version="3.0.1" />
     <PackageReference Include="Microsoft.ML.FastTree" Version="3.0.1" />
     <PackageReference Include="Microsoft.NETCore.App" Version="2.2.8" />
-    <PackageReference Include="mzLib" Version="1.0.549" />
+    <PackageReference Include="mzLib" Version="1.0.550" />
     <PackageReference Include="Nett" Version="0.15.0" />
   </ItemGroup>
 
diff --git a/MetaMorpheus/EngineLayer/EngineLayer.csproj b/MetaMorpheus/EngineLayer/EngineLayer.csproj
index c5ac735d8..a8621408a 100644
--- a/MetaMorpheus/EngineLayer/EngineLayer.csproj
+++ b/MetaMorpheus/EngineLayer/EngineLayer.csproj
@@ -21,7 +21,7 @@
     <PackageReference Include="Microsoft.ML.CpuMath" Version="3.0.1" />
     <PackageReference Include="Microsoft.ML.FastTree" Version="3.0.1" />
     <PackageReference Include="Microsoft.NETCore.App" Version="2.2.8" />
-    <PackageReference Include="mzLib" Version="1.0.549" />
+    <PackageReference Include="mzLib" Version="1.0.550" />
     <PackageReference Include="NETStandard.Library" Version="2.0.3" />
     <PackageReference Include="Nett" Version="0.15.0" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
diff --git a/MetaMorpheus/GUI/GUI.csproj b/MetaMorpheus/GUI/GUI.csproj
index 847b8abad..29027f365 100644
--- a/MetaMorpheus/GUI/GUI.csproj
+++ b/MetaMorpheus/GUI/GUI.csproj
@@ -54,7 +54,7 @@
     <PackageReference Include="Microsoft.ML.CpuMath" Version="3.0.1" />
     <PackageReference Include="Microsoft.ML.FastTree" Version="3.0.1" />
     <PackageReference Include="Microsoft.NETCore.App" Version="2.2.8" />
-    <PackageReference Include="mzLib" Version="1.0.549" />
+    <PackageReference Include="mzLib" Version="1.0.550" />
     <PackageReference Include="Nett" Version="0.15.0" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
     <PackageReference Include="OxyPlot.Core" Version="2.0.0" />
diff --git a/MetaMorpheus/GuiFunctions/GuiFunctions.csproj b/MetaMorpheus/GuiFunctions/GuiFunctions.csproj
index 5fdce1bcc..27f6145ae 100644
--- a/MetaMorpheus/GuiFunctions/GuiFunctions.csproj
+++ b/MetaMorpheus/GuiFunctions/GuiFunctions.csproj
@@ -15,7 +15,7 @@
   <ItemGroup>
     <PackageReference Include="itext7" Version="8.0.5" />
     <PackageReference Include="itext7.bouncy-castle-adapter" Version="8.0.5" />
-    <PackageReference Include="mzLib" Version="1.0.549" />
+    <PackageReference Include="mzLib" Version="1.0.550" />
     <PackageReference Include="OxyPlot.Wpf" Version="2.0.0" />
     <PackageReference Include="Svg" Version="3.4.7" />
   </ItemGroup>
diff --git a/MetaMorpheus/TaskLayer/TaskLayer.csproj b/MetaMorpheus/TaskLayer/TaskLayer.csproj
index af43b31d2..ded75a26e 100644
--- a/MetaMorpheus/TaskLayer/TaskLayer.csproj
+++ b/MetaMorpheus/TaskLayer/TaskLayer.csproj
@@ -21,7 +21,7 @@
     <PackageReference Include="Microsoft.ML.CpuMath" Version="3.0.1" />
     <PackageReference Include="Microsoft.ML.FastTree" Version="3.0.1" />
     <PackageReference Include="Microsoft.NETCore.App" Version="2.2.8" />
-    <PackageReference Include="mzLib" Version="1.0.549" />
+    <PackageReference Include="mzLib" Version="1.0.550" />
     <PackageReference Include="NetSerializer" Version="4.1.2" />
     <PackageReference Include="Nett" Version="0.15.0" />
   </ItemGroup>
diff --git a/MetaMorpheus/Test/PeptideSpectralMatchTest.cs b/MetaMorpheus/Test/PeptideSpectralMatchTest.cs
index 48591ebc3..9e6c9dcdf 100644
--- a/MetaMorpheus/Test/PeptideSpectralMatchTest.cs
+++ b/MetaMorpheus/Test/PeptideSpectralMatchTest.cs
@@ -33,7 +33,7 @@ public static void GetAminoAcidCoverageTest()
             int missedCleavages = 0;
             CleavageSpecificity cleavageSpecificity = CleavageSpecificity.Full;
             string peptideDescription = null;
-            int? pairedTargetDecoyHash = null;
+            string? pairedTargetDecoyHash = null;
 
             PeptideWithSetModifications pwsmNoBaseSequence = new(sequence, allKnownMods, numFixedMods, digestionParams, myProtein,
                 oneBasedStartResidueInProtein, oneBasedEndResidueInProtein, missedCleavages, cleavageSpecificity,
diff --git a/MetaMorpheus/Test/Test.csproj b/MetaMorpheus/Test/Test.csproj
index 870954444..154a19918 100644
--- a/MetaMorpheus/Test/Test.csproj
+++ b/MetaMorpheus/Test/Test.csproj
@@ -23,7 +23,7 @@
     <PackageReference Include="Microsoft.ML" Version="3.0.1" />
     <PackageReference Include="Microsoft.ML.CpuMath" Version="3.0.1" />
     <PackageReference Include="Microsoft.ML.FastTree" Version="3.0.1" />
-    <PackageReference Include="mzLib" Version="1.0.549" />
+    <PackageReference Include="mzLib" Version="1.0.550" />
     <PackageReference Include="NUnit" Version="4.1.0" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.6.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.10.0" />