diff --git a/.github/workflows/dotnetcore.yml b/.github/workflows/dotnetcore.yml
index 531454208..d36c81db9 100644
--- a/.github/workflows/dotnetcore.yml
+++ b/.github/workflows/dotnetcore.yml
@@ -12,7 +12,7 @@ jobs:
     - uses: actions/checkout@v1
     - uses: actions/setup-dotnet@v1
       with:
-        dotnet-version: 3.1.403
+        dotnet-version: 5.0.101
     - run: dotnet run -p build/build.csproj
     - uses: actions/upload-artifact@v2
       with:
diff --git a/build/Program.cs b/build/Program.cs
index 7c97ed0fe..81ac2a91e 100644
--- a/build/Program.cs
+++ b/build/Program.cs
@@ -46,7 +46,7 @@ void RemoveDirectory(string d)
             Run("dotnet", "format --check");
         });
 
-        Target(Build, DependsOn(Format), ForEach("net46", "netstandard2.0", "netstandard2.1"),
+        Target(Build, DependsOn(Format),
                framework =>
                {
                    if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && framework == "net46")
@@ -56,19 +56,19 @@ void RemoveDirectory(string d)
                    Run("dotnet", "build src/SharpCompress/SharpCompress.csproj -c Release");
                });
 
-        Target(Test, DependsOn(Build), ForEach("netcoreapp3.1"),
-            framework =>
-            {
-                IEnumerable<string> GetFiles(string d)
-                {
-                    return Glob.Files(".", d);
-                }
+        Target(Test, DependsOn(Build), ForEach("net5.0"),
+               framework =>
+               {
+                   IEnumerable<string> GetFiles(string d)
+                   {
+                       return Glob.Files(".", d);
+                   }
 
-                foreach (var file in GetFiles("**/*.Test.csproj"))
-                {
-                    Run("dotnet", $"test {file} -c Release -f {framework}");
-                }
-            });
+                   foreach (var file in GetFiles("**/*.Test.csproj"))
+                   {
+                       Run("dotnet", $"test {file} -c Release -f {framework}");
+                   }
+               });
 
         Target(Publish, DependsOn(Test),
                () =>
diff --git a/build/build.csproj b/build/build.csproj
index 2600bddad..635e5b012 100644
--- a/build/build.csproj
+++ b/build/build.csproj
@@ -2,13 +2,13 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <TargetFramework>net5.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Bullseye" Version="3.5.0" />
+    <PackageReference Include="Bullseye" Version="3.6.0" />
     <PackageReference Include="Glob" Version="1.1.8" />
-    <PackageReference Include="SimpleExec" Version="6.3.0" />
+    <PackageReference Include="SimpleExec" Version="6.4.0" />
   </ItemGroup>
 
 </Project>
diff --git a/global.json b/global.json
index 9731311d0..fbb332028 100644
--- a/global.json
+++ b/global.json
@@ -1,5 +1,5 @@
 {
   "sdk": {
-    "version": "3.1.403"
+    "version": "5.0.101"
   }
 }
\ No newline at end of file
diff --git a/src/SharpCompress/Algorithms/Alder32.cs b/src/SharpCompress/Algorithms/Alder32.cs
index d0b3279fd..06dfed524 100644
--- a/src/SharpCompress/Algorithms/Alder32.cs
+++ b/src/SharpCompress/Algorithms/Alder32.cs
@@ -4,7 +4,7 @@
 using System;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
-#if NETCOREAPP3_1
+#if !NETSTANDARD2_0 && !NETSTANDARD2_1
 using System.Runtime.Intrinsics;
 using System.Runtime.Intrinsics.X86;
 #endif
@@ -22,7 +22,7 @@ internal static class Adler32
         /// </summary>
         public const uint SeedValue = 1U;
 
-#if NETCOREAPP3_1
+#if !NETSTANDARD2_0 && !NETSTANDARD2_1
         private const int MinBufferSize = 64;
 #endif
 
@@ -56,7 +56,7 @@ public static uint Calculate(uint adler, ReadOnlySpan<byte> buffer)
                 return SeedValue;
             }
 
-#if NETCOREAPP3_1
+#if !NETSTANDARD2_0 && !NETSTANDARD2_1
             if (Sse3.IsSupported && buffer.Length >= MinBufferSize)
             {
                 return CalculateSse(adler, buffer);
@@ -69,7 +69,7 @@ public static uint Calculate(uint adler, ReadOnlySpan<byte> buffer)
         }
 
         // Based on https://github.com/chromium/chromium/blob/master/third_party/zlib/adler32_simd.c
-#if NETCOREAPP3_1
+#if !NETSTANDARD2_0 && !NETSTANDARD2_1
         private static unsafe uint CalculateSse(uint adler, ReadOnlySpan<byte> buffer)
         {
             uint s1 = adler & 0xFFFF;
diff --git a/src/SharpCompress/Archives/Zip/ZipArchive.cs b/src/SharpCompress/Archives/Zip/ZipArchive.cs
index 9994ccdd1..58d94ee0f 100644
--- a/src/SharpCompress/Archives/Zip/ZipArchive.cs
+++ b/src/SharpCompress/Archives/Zip/ZipArchive.cs
@@ -80,8 +80,7 @@ public static bool IsZipFile(Stream stream, string? password = null)
             StreamingZipHeaderFactory headerFactory = new StreamingZipHeaderFactory(password, new ArchiveEncoding());
             try
             {
-                ZipHeader header =
-                    headerFactory.ReadStreamHeader(stream).FirstOrDefault(x => x.ZipHeaderType != ZipHeaderType.Split);
+                ZipHeader? header = headerFactory.ReadStreamHeader(stream).FirstOrDefault(x => x.ZipHeaderType != ZipHeaderType.Split);
                 if (header is null)
                 {
                     return false;
diff --git a/src/SharpCompress/Common/Zip/StreamingZipHeaderFactory.cs b/src/SharpCompress/Common/Zip/StreamingZipHeaderFactory.cs
index 59953e534..3c273e326 100644
--- a/src/SharpCompress/Common/Zip/StreamingZipHeaderFactory.cs
+++ b/src/SharpCompress/Common/Zip/StreamingZipHeaderFactory.cs
@@ -49,7 +49,10 @@ internal IEnumerable<ZipHeader> ReadStreamHeader(Stream stream)
                 _lastEntryHeader = null;
                 uint headerBytes = reader.ReadUInt32();
                 header = ReadHeader(headerBytes, reader);
-                if (header is null) { yield break; }
+                if (header is null)
+                {
+                    yield break;
+                }
 
                 //entry could be zero bytes so we need to know that.
                 if (header.ZipHeaderType == ZipHeaderType.LocalEntry)
diff --git a/src/SharpCompress/Common/Zip/ZipFilePart.cs b/src/SharpCompress/Common/Zip/ZipFilePart.cs
index 6176bccf4..23fbaf24b 100644
--- a/src/SharpCompress/Common/Zip/ZipFilePart.cs
+++ b/src/SharpCompress/Common/Zip/ZipFilePart.cs
@@ -99,7 +99,7 @@ protected Stream CreateDecompressionStream(Stream stream, ZipCompressionMethod m
                     }
                 case ZipCompressionMethod.WinzipAes:
                     {
-                        ExtraData data = Header.Extra.Where(x => x.Type == ExtraDataType.WinZipAes).SingleOrDefault();
+                        ExtraData? data = Header.Extra.SingleOrDefault(x => x.Type == ExtraDataType.WinZipAes);
                         if (data is null)
                         {
                             throw new InvalidFormatException("No Winzip AES extra data found.");
diff --git a/src/SharpCompress/Common/Zip/ZipHeaderFactory.cs b/src/SharpCompress/Common/Zip/ZipHeaderFactory.cs
index 3e67e5af1..fac558d22 100644
--- a/src/SharpCompress/Common/Zip/ZipHeaderFactory.cs
+++ b/src/SharpCompress/Common/Zip/ZipHeaderFactory.cs
@@ -129,7 +129,7 @@ private void LoadHeader(ZipFileEntry entryHeader, Stream stream)
 
                 if (entryHeader.CompressionMethod == ZipCompressionMethod.WinzipAes)
                 {
-                    ExtraData data = entryHeader.Extra.SingleOrDefault(x => x.Type == ExtraDataType.WinZipAes);
+                    ExtraData? data = entryHeader.Extra.SingleOrDefault(x => x.Type == ExtraDataType.WinZipAes);
                     if (data != null)
                     {
                         var keySize = (WinzipAesKeySize)data.DataBytes[4];
diff --git a/src/SharpCompress/Compressors/BZip2/CBZip2OutputStream.cs b/src/SharpCompress/Compressors/BZip2/CBZip2OutputStream.cs
index a0e9705a0..b86695bdf 100644
--- a/src/SharpCompress/Compressors/BZip2/CBZip2OutputStream.cs
+++ b/src/SharpCompress/Compressors/BZip2/CBZip2OutputStream.cs
@@ -604,14 +604,7 @@ private void BsFinishedWithStream()
             while (bsLive > 0)
             {
                 int ch = (bsBuff >> 24);
-                try
-                {
-                    bsStream.WriteByte((byte)ch); // write 8-bit
-                }
-                catch (IOException e)
-                {
-                    throw e;
-                }
+                bsStream.WriteByte((byte)ch); // write 8-bit
                 bsBuff <<= 8;
                 bsLive -= 8;
                 bytesOut++;
@@ -623,14 +616,7 @@ private void BsW(int n, int v)
             while (bsLive >= 8)
             {
                 int ch = (bsBuff >> 24);
-                try
-                {
-                    bsStream.WriteByte((byte)ch); // write 8-bit
-                }
-                catch (IOException e)
-                {
-                    throw e;
-                }
+                bsStream.WriteByte((byte)ch); // write 8-bit
                 bsBuff <<= 8;
                 bsLive -= 8;
                 bytesOut++;
diff --git a/src/SharpCompress/Compressors/LZMA/AesDecoderStream.cs b/src/SharpCompress/Compressors/LZMA/AesDecoderStream.cs
index 7c2a81631..e59363dfe 100644
--- a/src/SharpCompress/Compressors/LZMA/AesDecoderStream.cs
+++ b/src/SharpCompress/Compressors/LZMA/AesDecoderStream.cs
@@ -31,7 +31,11 @@ public AesDecoderStream(Stream input, byte[] info, IPasswordProvider pass, long
             Init(info, out int numCyclesPower, out byte[] salt, out byte[] seed);
 
             byte[] password = Encoding.Unicode.GetBytes(pass.CryptoGetTextPassword());
-            byte[] key = InitKey(numCyclesPower, salt, password);
+            byte[]? key = InitKey(numCyclesPower, salt, password);
+            if (key == null)
+            {
+                throw new InvalidOperationException("Initialized with null key");
+            }
 
             using (var aes = Aes.Create())
             {
@@ -177,7 +181,7 @@ private void Init(byte[] info, out int numCyclesPower, out byte[] salt, out byte
             }
         }
 
-        private byte[] InitKey(int mNumCyclesPower, byte[] salt, byte[] pass)
+        private byte[]? InitKey(int mNumCyclesPower, byte[] salt, byte[] pass)
         {
             if (mNumCyclesPower == 0x3F)
             {
diff --git a/src/SharpCompress/SharpCompress.csproj b/src/SharpCompress/SharpCompress.csproj
index de803800e..b4ced089b 100644
--- a/src/SharpCompress/SharpCompress.csproj
+++ b/src/SharpCompress/SharpCompress.csproj
@@ -6,14 +6,12 @@
     <AssemblyVersion>0.26.0</AssemblyVersion>
     <FileVersion>0.26.0</FileVersion>
     <Authors>Adam Hathcock</Authors>
-    <TargetFrameworks Condition="'$(LibraryFrameworks)'==''">netstandard2.0;netstandard2.1;netcoreapp3.1;net461</TargetFrameworks>
-    <TargetFrameworks Condition=" '$(OS)' != 'Windows_NT' ">netstandard2.0;netstandard2.1;netcoreapp3.1;</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;netcoreapp3.1;net5.0</TargetFrameworks>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <AllowUnsafeBlocks>false</AllowUnsafeBlocks>
     <AssemblyName>SharpCompress</AssemblyName>
     <AssemblyOriginatorKeyFile>../../SharpCompress.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
-    <PublicSign Condition=" '$(OS)' != 'Windows_NT' ">true</PublicSign>
     <PackageId>SharpCompress</PackageId>
     <PackageTags>rar;unrar;zip;unzip;bzip2;gzip;tar;7zip;lzip;xz</PackageTags>
     <PackageProjectUrl>https://github.com/adamhathcock/sharpcompress</PackageProjectUrl>
@@ -31,14 +29,12 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0" PrivateAssets="All" />
+  </ItemGroup>  
+  <ItemGroup Condition=" '$(TargetFramework)' != 'net5.0' ">
+    <PackageReference Include="System.Text.Encoding.CodePages" Version="5.0.0" />
   </ItemGroup>
-
-
   <ItemGroup Condition=" '$(TargetFramework)' != 'netstandard2.1' ">
     <PackageReference Include="System.Memory" Version="4.5.4" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetFramework)' != 'net46' ">
-    <PackageReference Include="System.Text.Encoding.CodePages" Version="5.0.0" />
-  </ItemGroup>
 </Project>
diff --git a/tests/SharpCompress.Test/SharpCompress.Test.csproj b/tests/SharpCompress.Test/SharpCompress.Test.csproj
index 0c3d5d6f3..fbb420d63 100644
--- a/tests/SharpCompress.Test/SharpCompress.Test.csproj
+++ b/tests/SharpCompress.Test/SharpCompress.Test.csproj
@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>net461;netcoreapp3.1</TargetFrameworks>
+    <TargetFrameworks>net5.0</TargetFrameworks>
     <AssemblyName>SharpCompress.Test</AssemblyName>
     <AssemblyOriginatorKeyFile>../../SharpCompress.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
@@ -12,7 +12,7 @@
     <ProjectReference Include="..\..\src\SharpCompress\SharpCompress.csproj" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.8.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.8.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>