diff --git a/.circleci/config.yml b/.circleci/config.yml
index 2e01af9891a..2bac2f1a62c 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -112,36 +112,6 @@ commands:
         - "tools/*/bin/"
         - "tools/*/obj/"
 
-  mono_build_base:
-    steps:
-    - checkout
-    - concat_files:
-        glob: "{src,test,tools}/*/*.csproj"
-        to: .combined-package-files.txt
-    - restore_cache:
-        keys:
-        - v1-deps-{{ arch }}-{{ checksum ".combined-package-files.txt" }}
-        - v1-deps-{{ arch }}
-    - run: |
-        msbuild \
-          -t:Restore \
-          -p:Configuration=ReleaseMono \
-          -p:TestsTargetFramework=net47
-    - save_cache:
-        key: v1-deps-{{ arch }}-{{ checksum ".combined-package-files.txt" }}
-        paths:
-        - ~/.nuget/packages
-    - run: |
-        msbuild \
-          -p:Configuration=ReleaseMono \
-          -p:TestsTargetFramework=net47 \
-          -p:SkipSonar=true
-    - persist_to_workspace:
-        root: .
-        paths:
-        - "*/bin/"
-        - "*/obj/"
-
   netcore_test_base:
     parameters:
       collect_tests_from:
@@ -434,13 +404,6 @@ jobs:
     - netcore_build_base:
         collect_tests_filter: "<<parameters.collect_tests_filter>>"
 
-  linux-mono-build:
-    docker:
-    - image: mono:6.12
-    resource_class: xlarge
-    working_directory: /mnt/ramdisk
-    steps: [mono_build_base]
-
   linux-netcore-test-netmq:
     parameters:
       parallelism:
@@ -503,52 +466,11 @@ jobs:
     steps:
     - netcore_test_base: { code_coverage: false }
 
-  linux-unity-test:
-    docker:
-    - image: mono:6.12
-    environment:
-      XUNIT_UNITY_RUNNER: 0.5.0
-    resource_class: xlarge
-    working_directory: /mnt/ramdisk
-    parallelism: 4
-    steps:
-    - run:
-        name: Install xsltproc
-        command: apt update -y && apt install -y xsltproc
-    - unity_test_base
-
-  macos-unity-test:
-    macos:
-      xcode: 15.2.0
-    environment:
-      XUNIT_UNITY_RUNNER: 0.5.0
-    parallelism: 3
-    steps:
-    - ulimit: { n: 10240 }
-    - unity_test_base:
-        runner_target: StandaloneOSX
-
-  windows-unity-test:
-    executor:
-      name: win/default
-      size: xlarge
-    environment:
-      XUNIT_UNITY_RUNNER: 0.5.0
-    parallelism: 4
-    steps:
-    - run:
-        name: Install bzip2 & xsltproc
-        command: choco install bzip2 xsltproc
-    - unity_test_base:
-        runner_target: StandaloneWindows64
-
 workflows:
   main:
     jobs:
     - linux-netcore-build:
         collect_tests_filter: "FullyQualifiedName!~Libplanet.Net.Tests & CircleCI!=Skip"
-    # Temporarily tunred off by excluding of linux-unity-test
-    #- linux-mono-build
     - linux-netcore-test-netmq:
         requires: [linux-netcore-build]
     - linux-netcore-test-ar-SA:
@@ -559,15 +481,6 @@ workflows:
         requires: [linux-netcore-build]
     - windows-netcore-test:
         requires: [linux-netcore-build]
-    # Temporarily tunred off due to error on xunity-unity-runner:
-    #- linux-unity-test:
-    #    requires: [linux-mono-build]
-    # Temporarily turned off due to CircleCI's slow worker node assignments of
-    # macOS and Windows VMs:
-    #- macos-unity-test:
-    #    requires: [linux-mono-build]
-    #- windows-unity-test:
-    #    requires: [linux-mono-build]
   net:
     jobs:
     - linux-netcore-build:
@@ -577,10 +490,6 @@ workflows:
         name: linux-netcore-test-netmq-net
         requires: [linux-netcore-build-net]
         parallelism: 1
-    # - macos-netcore-test:
-    #     name: macos-netcore-test-net
-    #     requires: [linux-netcore-build-net]
-    #     parallelism: 1
     - windows-netcore-test:
         name: windows-netcore-test-net
         requires: [linux-netcore-build-net]
diff --git a/test/Libplanet.Analyzers.Tests/Libplanet.Analyzers.Tests.csproj b/test/Libplanet.Analyzers.Tests/Libplanet.Analyzers.Tests.csproj
index ad265eca19f..c52511c3516 100644
--- a/test/Libplanet.Analyzers.Tests/Libplanet.Analyzers.Tests.csproj
+++ b/test/Libplanet.Analyzers.Tests/Libplanet.Analyzers.Tests.csproj
@@ -7,10 +7,6 @@
     <NoWarn>$(NoWarn);SA1401</NoWarn>
   </PropertyGroup>
 
-  <PropertyGroup Condition=" '$(TestsTargetFramework)'!='' ">
-    <TargetFramework>$(TestsTargetFramework)</TargetFramework>
-  </PropertyGroup>
-
   <ItemGroup>
     <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.0" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="3.7.0" />
diff --git a/test/Libplanet.Crypto.Secp256k1.Tests/Libplanet.Crypto.Secp256k1.Tests.csproj b/test/Libplanet.Crypto.Secp256k1.Tests/Libplanet.Crypto.Secp256k1.Tests.csproj
index 73ba49854b3..e9b0254b78d 100644
--- a/test/Libplanet.Crypto.Secp256k1.Tests/Libplanet.Crypto.Secp256k1.Tests.csproj
+++ b/test/Libplanet.Crypto.Secp256k1.Tests/Libplanet.Crypto.Secp256k1.Tests.csproj
@@ -4,22 +4,10 @@
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
 
-  <PropertyGroup Condition=" '$(TestsTargetFramework)'!='' ">
-    <TargetFramework>$(TestsTargetFramework)</TargetFramework>
-  </PropertyGroup>
-
-  <PropertyGroup Condition=" '$(TestsTargetFramework)'!='' ">
-    <TargetFramework>$(TestsTargetFramework)</TargetFramework>
-  </PropertyGroup>
-
   <ItemGroup>
     <PackageReference Include="System.Collections.Immutable" Version="1.7.*" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetFramework)' == 'net47' ">
-    <PackageReference Include="System.ValueTuple" Version="4.5.0" />
-  </ItemGroup>
-
   <ItemGroup Condition="'$(SkipSonar)' != 'true'">
     <PackageReference Remove="SonarAnalyzer.CSharp" />
   </ItemGroup>
diff --git a/test/Libplanet.Explorer.Cocona.Tests/Libplanet.Explorer.Cocona.Tests.csproj b/test/Libplanet.Explorer.Cocona.Tests/Libplanet.Explorer.Cocona.Tests.csproj
index bce258834fc..4ac5fb683c8 100644
--- a/test/Libplanet.Explorer.Cocona.Tests/Libplanet.Explorer.Cocona.Tests.csproj
+++ b/test/Libplanet.Explorer.Cocona.Tests/Libplanet.Explorer.Cocona.Tests.csproj
@@ -4,14 +4,6 @@
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
 
-  <PropertyGroup Condition=" '$(TestsTargetFramework)'!='' ">
-    <TargetFramework>$(TestsTargetFramework)</TargetFramework>
-  </PropertyGroup>
-
-  <PropertyGroup Condition=" '$(TestsTargetFramework)'!='' ">
-    <TargetFramework>$(TestsTargetFramework)</TargetFramework>
-  </PropertyGroup>
-
   <ItemGroup>
     <ProjectReference Include="..\..\tools\Libplanet.Explorer.Cocona\Libplanet.Explorer.Cocona.csproj" />
     <ProjectReference Include="..\Libplanet.Explorer.Tests\Libplanet.Explorer.Tests.csproj" />
diff --git a/test/Libplanet.Extensions.Cocona.Tests/Libplanet.Extensions.Cocona.Tests.csproj b/test/Libplanet.Extensions.Cocona.Tests/Libplanet.Extensions.Cocona.Tests.csproj
index 2986f521871..e071bea4ea8 100644
--- a/test/Libplanet.Extensions.Cocona.Tests/Libplanet.Extensions.Cocona.Tests.csproj
+++ b/test/Libplanet.Extensions.Cocona.Tests/Libplanet.Extensions.Cocona.Tests.csproj
@@ -4,14 +4,6 @@
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
 
-  <PropertyGroup Condition=" '$(TestsTargetFramework)'!='' ">
-    <TargetFramework>$(TestsTargetFramework)</TargetFramework>
-  </PropertyGroup>
-
-  <PropertyGroup Condition=" '$(TestsTargetFramework)'!='' ">
-    <TargetFramework>$(TestsTargetFramework)</TargetFramework>
-  </PropertyGroup>
-
   <ItemGroup>
     <PackageReference Include="System.Collections.Immutable" Version="1.7.*" />
   </ItemGroup>
diff --git a/test/Libplanet.Net.Tests/Libplanet.Net.Tests.csproj b/test/Libplanet.Net.Tests/Libplanet.Net.Tests.csproj
index 8c682cce218..f5ed26774a3 100644
--- a/test/Libplanet.Net.Tests/Libplanet.Net.Tests.csproj
+++ b/test/Libplanet.Net.Tests/Libplanet.Net.Tests.csproj
@@ -6,10 +6,6 @@
     <NoWarn>$(NoWarn);SA1401;SYSLIB0011</NoWarn>
   </PropertyGroup>
 
-  <PropertyGroup Condition=" '$(TestsTargetFramework)'!='' ">
-    <TargetFramework>$(TestsTargetFramework)</TargetFramework>
-  </PropertyGroup>
-
   <ItemGroup>
     <PackageReference Include="Xunit.SkippableFact" Version="1.3.12" />
   </ItemGroup>
@@ -21,15 +17,4 @@
     <ProjectReference Include="..\Libplanet.Tests\Libplanet.Tests.csproj" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(MSBuildRuntimeType)'=='Mono' ">
-    <!--
-    As Mono has no proper AppDomain, we prevent it on Mono.
-    This works around Xunit's fatal error on Mono.
-    -->
-    <Content Include="xunit.runner.mono.json">
-      <Link>xunit.runner.json</Link>
-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-    </Content>
-  </ItemGroup>
-
 </Project>
diff --git a/test/Libplanet.RocksDBStore.Tests/Libplanet.RocksDBStore.Tests.csproj b/test/Libplanet.RocksDBStore.Tests/Libplanet.RocksDBStore.Tests.csproj
index dec82cd3eb1..9ef2cf2e40b 100644
--- a/test/Libplanet.RocksDBStore.Tests/Libplanet.RocksDBStore.Tests.csproj
+++ b/test/Libplanet.RocksDBStore.Tests/Libplanet.RocksDBStore.Tests.csproj
@@ -6,20 +6,12 @@
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
 
-  <PropertyGroup Condition=" '$(TestsTargetFramework)'!='' ">
-    <TargetFramework>$(TestsTargetFramework)</TargetFramework>
-  </PropertyGroup>
-
   <ItemGroup>
     <PackageReference Include="Serilog.Enrichers.Thread" Version="3.0.0" />
     <PackageReference Include="Serilog.Sinks.XUnit" Version="1.0.7" />
     <PackageReference Include="System.Collections.Immutable" Version="1.7.*" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetFramework)' == 'net47' ">
-    <PackageReference Include="System.ValueTuple" Version="4.5.0" />
-  </ItemGroup>
-
   <ItemGroup>
     <ProjectReference Include="..\..\src\Libplanet.RocksDBStore\Libplanet.RocksDBStore.csproj" />
     <ProjectReference Include="..\Libplanet.Tests\Libplanet.Tests.csproj" />
diff --git a/test/Libplanet.Stun.Tests/Libplanet.Stun.Tests.csproj b/test/Libplanet.Stun.Tests/Libplanet.Stun.Tests.csproj
index 70814fd0287..d6bae30061b 100644
--- a/test/Libplanet.Stun.Tests/Libplanet.Stun.Tests.csproj
+++ b/test/Libplanet.Stun.Tests/Libplanet.Stun.Tests.csproj
@@ -6,22 +6,8 @@
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
 
-  <PropertyGroup Condition=" '$(TestsTargetFramework)'!='' ">
-    <TargetFramework>$(TestsTargetFramework)</TargetFramework>
-  </PropertyGroup>
-
   <ItemGroup>
     <ProjectReference Include="..\..\src\Libplanet.Stun\Libplanet.Stun.csproj" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(MSBuildRuntimeType)'=='Mono' ">
-    <!--
-    As Mono has no proper AppDomain, we prevent it on Mono.
-    This works around Xunit's fatal error on Mono.
-    -->
-    <Content Include="xunit.runner.mono.json">
-      <Link>xunit.runner.json</Link>
-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-    </Content>
-  </ItemGroup>
 </Project>
diff --git a/test/Libplanet.Tests/Libplanet.Tests.csproj b/test/Libplanet.Tests/Libplanet.Tests.csproj
index 4af7021923e..35a19efc6fe 100644
--- a/test/Libplanet.Tests/Libplanet.Tests.csproj
+++ b/test/Libplanet.Tests/Libplanet.Tests.csproj
@@ -14,10 +14,6 @@
     </AdditionalFiles>
   </ItemGroup>
 
-  <PropertyGroup Condition=" '$(TestsTargetFramework)'!='' ">
-    <TargetFramework>$(TestsTargetFramework)</TargetFramework>
-  </PropertyGroup>
-
   <ItemGroup>
     <PackageReference Include="AsyncEnumerator" Version="4.0.2" />
     <PackageReference Include="DiffPlex" Version="1.7.0" />
@@ -44,15 +40,4 @@
     <ProjectReference Include="..\Libplanet.Mocks\Libplanet.Mocks.csproj" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(MSBuildRuntimeType)'=='Mono' ">
-    <!--
-    As Mono has no proper AppDomain, we prevent it on Mono.
-    This works around Xunit's fatal error on Mono.
-    -->
-    <Content Include="xunit.runner.mono.json">
-      <Link>xunit.runner.json</Link>
-      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-    </Content>
-  </ItemGroup>
-
 </Project>
diff --git a/tools/Libplanet.Tools/Libplanet.Tools.csproj b/tools/Libplanet.Tools/Libplanet.Tools.csproj
index 3695df40ac1..acf220651cf 100644
--- a/tools/Libplanet.Tools/Libplanet.Tools.csproj
+++ b/tools/Libplanet.Tools/Libplanet.Tools.csproj
@@ -28,12 +28,6 @@
     <InvariantGlobalization>true</InvariantGlobalization>
   </PropertyGroup>
 
-  <!-- Workaround for the build env with Mono. -->
-  <!-- After considering about we really need the Mono as build env, it may be needed to delete. -->
-  <PropertyGroup Condition=" '$(MSBuildRuntimeType)' == 'Mono' ">
-    <TargetFramework>netcoreapp3.1</TargetFramework>
-  </PropertyGroup>
-
   <ItemGroup>
     <None Remove="..\..\README.md" />
     <None Include="README.md" Pack="true" PackagePath="README.md" />