diff --git a/src/DotRecast.Core/DotRecast.Core.csproj b/src/DotRecast.Core/DotRecast.Core.csproj
index 185f7bb..83c0d59 100644
--- a/src/DotRecast.Core/DotRecast.Core.csproj
+++ b/src/DotRecast.Core/DotRecast.Core.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.1;net7.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.1;net6.0;net7.0</TargetFrameworks>
     <PackageId>DotRecast.Core</PackageId>
     <PackageReadmeFile>README.md</PackageReadmeFile>
     <Authors>ikpil</Authors>
diff --git a/src/DotRecast.Detour.Crowd/DotRecast.Detour.Crowd.csproj b/src/DotRecast.Detour.Crowd/DotRecast.Detour.Crowd.csproj
index 7a56641..07db032 100644
--- a/src/DotRecast.Detour.Crowd/DotRecast.Detour.Crowd.csproj
+++ b/src/DotRecast.Detour.Crowd/DotRecast.Detour.Crowd.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.1;net7.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.1;net6.0;net7.0</TargetFrameworks>
     <PackageId>DotRecast.Detour.Crowd</PackageId>
     <PackageReadmeFile>README.md</PackageReadmeFile>
     <Authors>ikpil</Authors>
diff --git a/src/DotRecast.Detour.Dynamic/DotRecast.Detour.Dynamic.csproj b/src/DotRecast.Detour.Dynamic/DotRecast.Detour.Dynamic.csproj
index 0d6c6a1..5b12ac0 100644
--- a/src/DotRecast.Detour.Dynamic/DotRecast.Detour.Dynamic.csproj
+++ b/src/DotRecast.Detour.Dynamic/DotRecast.Detour.Dynamic.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.1;net7.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.1;net6.0;net7.0</TargetFrameworks>
     <PackageId>DotRecast.Detour.Dynamic</PackageId>
     <PackageReadmeFile>README.md</PackageReadmeFile>
     <Authors>ikpil</Authors>
diff --git a/src/DotRecast.Detour.Extras/DotRecast.Detour.Extras.csproj b/src/DotRecast.Detour.Extras/DotRecast.Detour.Extras.csproj
index de499e1..7671c02 100644
--- a/src/DotRecast.Detour.Extras/DotRecast.Detour.Extras.csproj
+++ b/src/DotRecast.Detour.Extras/DotRecast.Detour.Extras.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.1;net7.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.1;net6.0;net7.0</TargetFrameworks>
     <PackageId>DotRecast.Detour.Extras</PackageId>
     <PackageReadmeFile>README.md</PackageReadmeFile>
     <Authors>ikpil</Authors>
diff --git a/src/DotRecast.Detour.TileCache/DotRecast.Detour.TileCache.csproj b/src/DotRecast.Detour.TileCache/DotRecast.Detour.TileCache.csproj
index 4d21759..967e77f 100644
--- a/src/DotRecast.Detour.TileCache/DotRecast.Detour.TileCache.csproj
+++ b/src/DotRecast.Detour.TileCache/DotRecast.Detour.TileCache.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.1;net7.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.1;net6.0;net7.0</TargetFrameworks>
     <PackageId>DotRecast.Detour.TileCache</PackageId>
     <PackageReadmeFile>README.md</PackageReadmeFile>
     <Authors>ikpil</Authors>
diff --git a/src/DotRecast.Detour/DotRecast.Detour.csproj b/src/DotRecast.Detour/DotRecast.Detour.csproj
index 804e67f..3b47a56 100644
--- a/src/DotRecast.Detour/DotRecast.Detour.csproj
+++ b/src/DotRecast.Detour/DotRecast.Detour.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.1;net7.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.1;net6.0;net7.0</TargetFrameworks>
     <PackageId>DotRecast.Detour</PackageId>
     <PackageReadmeFile>README.md</PackageReadmeFile>
     <Authors>ikpil</Authors>
diff --git a/src/DotRecast.Recast.Demo/DotRecast.Recast.Demo.csproj b/src/DotRecast.Recast.Demo/DotRecast.Recast.Demo.csproj
index 23ab75e..de7a8c6 100644
--- a/src/DotRecast.Recast.Demo/DotRecast.Recast.Demo.csproj
+++ b/src/DotRecast.Recast.Demo/DotRecast.Recast.Demo.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFrameworks>net6.0;net7.0</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <PackageId>DotRecast.Recast.Demo</PackageId>
     <PackageReadmeFile>README.md</PackageReadmeFile>
diff --git a/src/DotRecast.Recast.Demo/Draw/DebugDraw.cs b/src/DotRecast.Recast.Demo/Draw/DebugDraw.cs
index b481814..875f17b 100644
--- a/src/DotRecast.Recast.Demo/Draw/DebugDraw.cs
+++ b/src/DotRecast.Recast.Demo/Draw/DebugDraw.cs
@@ -587,7 +587,8 @@ public class DebugDraw
 
     public static int Bit(int a, int b)
     {
-        return (a & (1 << b)) >>> b;
+        //return (a & (1 << b)) >>> b;
+        return (a >> b) & 1;
     }
 
     public static int DuIntToCol(int i, int a)
diff --git a/src/DotRecast.Recast.Demo/Draw/ModernOpenGLDraw.cs b/src/DotRecast.Recast.Demo/Draw/ModernOpenGLDraw.cs
index 0a4e41f..8ca2ed6 100644
--- a/src/DotRecast.Recast.Demo/Draw/ModernOpenGLDraw.cs
+++ b/src/DotRecast.Recast.Demo/Draw/ModernOpenGLDraw.cs
@@ -129,9 +129,9 @@ public class ModernOpenGLDraw : IOpenGLDraw
         // _gl.VertexAttribP3(attrib_pos, GLEnum.Float, false, 24);
         // _gl.VertexAttribP2(attrib_uv, GLEnum.Float, false, 24);
         // _gl.VertexAttribP4(attrib_col, GLEnum.UnsignedByte, true, 24);
-        IntPtr pointer1 = 0;
-        IntPtr pointer2 = 12;
-        IntPtr pointer3 = 20;
+        IntPtr pointer1 = (IntPtr)0;
+        IntPtr pointer2 = (IntPtr)12;
+        IntPtr pointer3 = (IntPtr)20;
         _gl.VertexAttribPointer(attrib_pos, 3, VertexAttribPointerType.Float, false, 24, pointer1.ToPointer());
         _gl.VertexAttribPointer(attrib_uv, 2, VertexAttribPointerType.Float, false, 24, pointer2.ToPointer());
         _gl.VertexAttribPointer(attrib_col, 4, VertexAttribPointerType.UnsignedByte, true, 24, pointer3.ToPointer());
diff --git a/src/DotRecast.Recast.Demo/Messages/GeomLoadBeganEvent.cs b/src/DotRecast.Recast.Demo/Messages/GeomLoadBeganEvent.cs
index 28bf422..c4fffb8 100644
--- a/src/DotRecast.Recast.Demo/Messages/GeomLoadBeganEvent.cs
+++ b/src/DotRecast.Recast.Demo/Messages/GeomLoadBeganEvent.cs
@@ -2,5 +2,5 @@
 
 public class GeomLoadBeganEvent : IRecastDemoMessage
 {
-    public required string FilePath { get; init; }
+    public string FilePath { get; init; }
 }
\ No newline at end of file
diff --git a/src/DotRecast.Recast.Demo/Messages/NavMeshLoadBeganEvent.cs b/src/DotRecast.Recast.Demo/Messages/NavMeshLoadBeganEvent.cs
index 3895b32..e549788 100644
--- a/src/DotRecast.Recast.Demo/Messages/NavMeshLoadBeganEvent.cs
+++ b/src/DotRecast.Recast.Demo/Messages/NavMeshLoadBeganEvent.cs
@@ -2,5 +2,5 @@
 
 public class NavMeshLoadBeganEvent : IRecastDemoMessage
 {
-    public required string FilePath { get; init; }
+    public string FilePath { get; init; }
 }
\ No newline at end of file
diff --git a/src/DotRecast.Recast.Demo/Messages/RaycastEvent.cs b/src/DotRecast.Recast.Demo/Messages/RaycastEvent.cs
index 916fca1..da45ce3 100644
--- a/src/DotRecast.Recast.Demo/Messages/RaycastEvent.cs
+++ b/src/DotRecast.Recast.Demo/Messages/RaycastEvent.cs
@@ -4,6 +4,6 @@ namespace DotRecast.Recast.Demo.Messages;
 
 public class RaycastEvent : IRecastDemoMessage
 {
-    public required RcVec3f Start { get; init; }
-    public required RcVec3f End { get; init; }
+    public RcVec3f Start { get; init; }
+    public RcVec3f End { get; init; }
 }
\ No newline at end of file
diff --git a/src/DotRecast.Recast.Demo/UI/ViewModels/LogMessageItem.cs b/src/DotRecast.Recast.Demo/UI/ViewModels/LogMessageItem.cs
index 7ff365b..cba0b0d 100644
--- a/src/DotRecast.Recast.Demo/UI/ViewModels/LogMessageItem.cs
+++ b/src/DotRecast.Recast.Demo/UI/ViewModels/LogMessageItem.cs
@@ -2,6 +2,6 @@
 
 public class LogMessageItem
 {
-    public required int Level { get; init; }
-    public required string Message { get; init; }
+    public int Level { get; init; }
+    public string Message { get; init; }
 }
\ No newline at end of file
diff --git a/src/DotRecast.Recast.Toolset/DotRecast.Recast.Toolset.csproj b/src/DotRecast.Recast.Toolset/DotRecast.Recast.Toolset.csproj
index 803645e..61edc1c 100644
--- a/src/DotRecast.Recast.Toolset/DotRecast.Recast.Toolset.csproj
+++ b/src/DotRecast.Recast.Toolset/DotRecast.Recast.Toolset.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.1;net7.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.1;net6.0;net7.0</TargetFrameworks>
     <PackageId>DotRecast.Recast.Toolset</PackageId>
     <PackageReadmeFile>README.md</PackageReadmeFile>
     <Authors>ikpil</Authors>
diff --git a/src/DotRecast.Recast/DotRecast.Recast.csproj b/src/DotRecast.Recast/DotRecast.Recast.csproj
index 24969f6..102b48b 100644
--- a/src/DotRecast.Recast/DotRecast.Recast.csproj
+++ b/src/DotRecast.Recast/DotRecast.Recast.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.1;net7.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.1;net6.0;net7.0</TargetFrameworks>
     <PackageId>DotRecast.Recast</PackageId>
     <PackageReadmeFile>README.md</PackageReadmeFile>
     <Authors>ikpil</Authors>
diff --git a/test/DotRecast.Core.Test/DotRecast.Core.Test.csproj b/test/DotRecast.Core.Test/DotRecast.Core.Test.csproj
index 9fefde3..23d3256 100644
--- a/test/DotRecast.Core.Test/DotRecast.Core.Test.csproj
+++ b/test/DotRecast.Core.Test/DotRecast.Core.Test.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>net7.0</TargetFramework>
+        <TargetFrameworks>net6.0;net7.0</TargetFrameworks>
         <IsPackable>false</IsPackable>
         <IsTestProject>true</IsTestProject>
     </PropertyGroup>
diff --git a/test/DotRecast.Detour.Crowd.Test/DotRecast.Detour.Crowd.Test.csproj b/test/DotRecast.Detour.Crowd.Test/DotRecast.Detour.Crowd.Test.csproj
index 2f624f0..ce42ce2 100644
--- a/test/DotRecast.Detour.Crowd.Test/DotRecast.Detour.Crowd.Test.csproj
+++ b/test/DotRecast.Detour.Crowd.Test/DotRecast.Detour.Crowd.Test.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>net7.0</TargetFramework>
+        <TargetFrameworks>net6.0;net7.0</TargetFrameworks>
         <IsPackable>false</IsPackable>
         <IsTestProject>true</IsTestProject>
     </PropertyGroup>
diff --git a/test/DotRecast.Detour.Dynamic.Test/DotRecast.Detour.Dynamic.Test.csproj b/test/DotRecast.Detour.Dynamic.Test/DotRecast.Detour.Dynamic.Test.csproj
index 7cbc136..1b07b72 100644
--- a/test/DotRecast.Detour.Dynamic.Test/DotRecast.Detour.Dynamic.Test.csproj
+++ b/test/DotRecast.Detour.Dynamic.Test/DotRecast.Detour.Dynamic.Test.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>net7.0</TargetFramework>
+        <TargetFrameworks>net6.0;net7.0</TargetFrameworks>
         <IsPackable>false</IsPackable>
         <IsTestProject>true</IsTestProject>
     </PropertyGroup>
diff --git a/test/DotRecast.Detour.Extras.Test/DotRecast.Detour.Extras.Test.csproj b/test/DotRecast.Detour.Extras.Test/DotRecast.Detour.Extras.Test.csproj
index 4cd7809..b45d9c8 100644
--- a/test/DotRecast.Detour.Extras.Test/DotRecast.Detour.Extras.Test.csproj
+++ b/test/DotRecast.Detour.Extras.Test/DotRecast.Detour.Extras.Test.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>net7.0</TargetFramework>
+        <TargetFrameworks>net6.0;net7.0</TargetFrameworks>
         <IsPackable>false</IsPackable>
         <IsTestProject>true</IsTestProject>
     </PropertyGroup>
diff --git a/test/DotRecast.Detour.Test/DotRecast.Detour.Test.csproj b/test/DotRecast.Detour.Test/DotRecast.Detour.Test.csproj
index 1a13a5f..2e88dc9 100644
--- a/test/DotRecast.Detour.Test/DotRecast.Detour.Test.csproj
+++ b/test/DotRecast.Detour.Test/DotRecast.Detour.Test.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>net7.0</TargetFramework>
+        <TargetFrameworks>net6.0;net7.0</TargetFrameworks>
         <IsPackable>false</IsPackable>
         <IsTestProject>true</IsTestProject>
     </PropertyGroup>
diff --git a/test/DotRecast.Detour.TileCache.Test/DotRecast.Detour.TileCache.Test.csproj b/test/DotRecast.Detour.TileCache.Test/DotRecast.Detour.TileCache.Test.csproj
index 2f95f2e..93bb27b 100644
--- a/test/DotRecast.Detour.TileCache.Test/DotRecast.Detour.TileCache.Test.csproj
+++ b/test/DotRecast.Detour.TileCache.Test/DotRecast.Detour.TileCache.Test.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>net7.0</TargetFramework>
+        <TargetFrameworks>net6.0;net7.0</TargetFrameworks>
         <IsPackable>false</IsPackable>
         <IsTestProject>true</IsTestProject>
     </PropertyGroup>
diff --git a/test/DotRecast.Recast.Test/DotRecast.Recast.Test.csproj b/test/DotRecast.Recast.Test/DotRecast.Recast.Test.csproj
index efa7118..92874a1 100644
--- a/test/DotRecast.Recast.Test/DotRecast.Recast.Test.csproj
+++ b/test/DotRecast.Recast.Test/DotRecast.Recast.Test.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>net7.0</TargetFramework>
+        <TargetFrameworks>net6.0;net7.0</TargetFrameworks>
         <IsPackable>false</IsPackable>
         <IsTestProject>true</IsTestProject>
     </PropertyGroup>