diff --git a/src/SharpCompress/Common/ExtractionMethods.cs b/src/SharpCompress/Common/ExtractionMethods.cs
index 81be96f5..0e3492be 100644
--- a/src/SharpCompress/Common/ExtractionMethods.cs
+++ b/src/SharpCompress/Common/ExtractionMethods.cs
@@ -24,7 +24,7 @@ namespace SharpCompress.Common
 
             if (options.ExtractFullPath)
             {
-                string folder = Path.GetDirectoryName(entry.Key);
+                string folder = Path.GetDirectoryName(entry.Key)!;
                 string destdir = Path.GetFullPath(Path.Combine(fullDestinationDirectoryPath, folder));
 
                 if (!Directory.Exists(destdir))
diff --git a/src/SharpCompress/Common/Rar/Headers/NewSubHeaderType.cs b/src/SharpCompress/Common/Rar/Headers/NewSubHeaderType.cs
index 84d50aee..647d43e6 100644
--- a/src/SharpCompress/Common/Rar/Headers/NewSubHeaderType.cs
+++ b/src/SharpCompress/Common/Rar/Headers/NewSubHeaderType.cs
@@ -37,6 +37,7 @@ namespace SharpCompress.Common.Rar.Headers
             {
                 return false;
             }
+
             for (int i = 0; i < bytes.Length; ++i)
             {
                 if (_bytes[i] != bytes[i])
@@ -47,9 +48,9 @@ namespace SharpCompress.Common.Rar.Headers
             return true;
         }
 
-        public bool Equals(NewSubHeaderType other)
+        public bool Equals(NewSubHeaderType? other)
         {
-            return Equals(other._bytes);
+            return other is not null && Equals(other._bytes);
         }
     }
 }
\ No newline at end of file
diff --git a/src/SharpCompress/Common/SevenZip/CMethodId.cs b/src/SharpCompress/Common/SevenZip/CMethodId.cs
index 03ce8df6..5069b051 100644
--- a/src/SharpCompress/Common/SevenZip/CMethodId.cs
+++ b/src/SharpCompress/Common/SevenZip/CMethodId.cs
@@ -24,7 +24,7 @@
             return _id.GetHashCode();
         }
 
-        public override bool Equals(object obj)
+        public override bool Equals(object? obj)
         {
             return obj is CMethodId other && Equals(other);
         }
diff --git a/src/SharpCompress/Compressors/Deflate/GZipStream.cs b/src/SharpCompress/Compressors/Deflate/GZipStream.cs
index 6107db65..903cea2c 100644
--- a/src/SharpCompress/Compressors/Deflate/GZipStream.cs
+++ b/src/SharpCompress/Compressors/Deflate/GZipStream.cs
@@ -447,7 +447,7 @@ namespace SharpCompress.Compressors.Deflate
             // filename
             if (fnLength != 0)
             {
-                Array.Copy(filenameBytes, 0, header, i, fnLength - 1);
+                Array.Copy(filenameBytes!, 0, header, i, fnLength - 1);
                 i += fnLength - 1;
                 header[i++] = 0; // terminate
             }
@@ -455,7 +455,7 @@ namespace SharpCompress.Compressors.Deflate
             // comment
             if (cbLength != 0)
             {
-                Array.Copy(commentBytes, 0, header, i, cbLength - 1);
+                Array.Copy(commentBytes!, 0, header, i, cbLength - 1);
                 i += cbLength - 1;
                 header[i++] = 0; // terminate
             }
diff --git a/src/SharpCompress/Compressors/Xz/Filters/BlockFilter.cs b/src/SharpCompress/Compressors/Xz/Filters/BlockFilter.cs
index bf6d85e5..875d1b44 100644
--- a/src/SharpCompress/Compressors/Xz/Filters/BlockFilter.cs
+++ b/src/SharpCompress/Compressors/Xz/Filters/BlockFilter.cs
@@ -39,7 +39,7 @@ namespace SharpCompress.Compressors.Xz.Filters
                 throw new NotImplementedException($"Filter {filterType} has not yet been implemented");
             }
 
-            var filter = (BlockFilter)Activator.CreateInstance(FilterMap[filterType]);
+            var filter = (BlockFilter)Activator.CreateInstance(FilterMap[filterType])!;
 
             var sizeOfProperties = reader.ReadXZInteger();
             if (sizeOfProperties > int.MaxValue)
diff --git a/src/SharpCompress/SharpCompress.csproj b/src/SharpCompress/SharpCompress.csproj
index cb6f21b1..de803800 100644
--- a/src/SharpCompress/SharpCompress.csproj
+++ b/src/SharpCompress/SharpCompress.csproj
@@ -6,8 +6,8 @@
     <AssemblyVersion>0.26.0</AssemblyVersion>
     <FileVersion>0.26.0</FileVersion>
     <Authors>Adam Hathcock</Authors>
-    <TargetFrameworks Condition="'$(LibraryFrameworks)'==''">netstandard2.0;netstandard2.1;net461</TargetFrameworks>
-    <TargetFrameworks Condition=" '$(OS)' != 'Windows_NT' ">netstandard2.0;netstandard2.1</TargetFrameworks>
+    <TargetFrameworks Condition="'$(LibraryFrameworks)'==''">netstandard2.0;netstandard2.1;netcoreapp3.1;net461</TargetFrameworks>
+    <TargetFrameworks Condition=" '$(OS)' != 'Windows_NT' ">netstandard2.0;netstandard2.1;netcoreapp3.1;</TargetFrameworks>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <AllowUnsafeBlocks>false</AllowUnsafeBlocks>
     <AssemblyName>SharpCompress</AssemblyName>
@@ -23,6 +23,7 @@
     <Description>SharpCompress is a compression library for NET Standard 2.0/2.1//NET 4.6 that can unrar, decompress 7zip, decompress xz, zip/unzip, tar/untar lzip/unlzip, bzip2/unbzip2 and gzip/ungzip with forward-only reading and file random access APIs. Write support for zip/tar/bzip2/gzip is implemented.</Description>
     <LangVersion>9</LangVersion>
     <Nullable>enable</Nullable>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <PublishRepositoryUrl>true</PublishRepositoryUrl>
     <IncludeSymbols>true</IncludeSymbols>
     <SymbolPackageFormat>snupkg</SymbolPackageFormat>