diff --git a/FastCache/FastCache.cs b/FastCache/FastCache.cs
index db0bb93..0e7ca8f 100644
--- a/FastCache/FastCache.cs
+++ b/FastCache/FastCache.cs
@@ -14,6 +14,7 @@ public class FastCache<TKey, TValue> : IEnumerable<KeyValuePair<TKey, TValue>>,
 	{
 		private readonly ConcurrentDictionary<TKey, TtlValue> _dict = new ConcurrentDictionary<TKey, TtlValue>();
 
+		private readonly Lock _lock = new();
 		private readonly Timer _cleanUpTimer;
 		private readonly EvictionCallback _itemEvicted;
 
@@ -61,7 +62,7 @@ await _globalStaticLock.WaitAsync()
 		public void EvictExpired()
 		{
 			//Eviction already started by another thread? forget it, lets move on
-			if (Monitor.TryEnter(_cleanUpTimer)) //use the timer-object for our lock, it's local, private and instance-type, so its ok
+			if (_lock.TryEnter()) //use the timer-object for our lock, it's local, private and instance-type, so its ok
 			{
 				List<TKey> evictedKeys = null; // Batch eviction callbacks
 				try
@@ -86,7 +87,7 @@ public void EvictExpired()
 				}
 				finally
 				{
-					Monitor.Exit(_cleanUpTimer);
+                    _lock.Exit();
 				}
 
 				// Trigger batched eviction callbacks outside the loop to prevent flooding the thread pool
diff --git a/FastCache/FastCache.csproj b/FastCache/FastCache.csproj
index 5d2b925..49f01c5 100644
--- a/FastCache/FastCache.csproj
+++ b/FastCache/FastCache.csproj
@@ -1,30 +1,38 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
-  <PropertyGroup>
-    <TargetFrameworks>net6.0;net8.0</TargetFrameworks>
-    <PackageId>Jitbit.FastCache</PackageId>
-    <Title>FastCache</Title>
-    <Authors>Alex from Jitbit</Authors>
-    <Product>FastCache</Product>
-    <PackageProjectUrl>https://github.com/jitbit/fastcache</PackageProjectUrl>
-    <PackageReadmeFile>README.md</PackageReadmeFile>
-    <RepositoryUrl>https://github.com/jitbit/fastcache</RepositoryUrl>
-    <PackageLicenseFile>LICENSE</PackageLicenseFile>
-	<Version>1.1.0</Version>
-	<PackageTags>cache;caching;MemoryCache</PackageTags>
-	<Description>Fastest in-memoery cache for .NET</Description>
-	<GenerateDocumentationFile>True</GenerateDocumentationFile>
-  </PropertyGroup>
+	<PropertyGroup>
+		<TargetFrameworks>net6.0;net8.0;net9.0</TargetFrameworks>
+		<LangVersion>latest</LangVersion>
+		<PackageId>Jitbit.FastCache</PackageId>
+		<Title>FastCache</Title>
+		<Authors>Alex from Jitbit</Authors>
+		<Product>FastCache</Product>
+		<PackageProjectUrl>https://github.com/jitbit/fastcache</PackageProjectUrl>
+		<PackageReadmeFile>README.md</PackageReadmeFile>
+		<RepositoryUrl>https://github.com/jitbit/fastcache</RepositoryUrl>
+		<PackageLicenseFile>LICENSE</PackageLicenseFile>
+		<Version>1.1.0</Version>
+		<PackageTags>cache;caching;MemoryCache</PackageTags>
+		<Description>Fastest in-memoery cache for .NET</Description>
+		<GenerateDocumentationFile>True</GenerateDocumentationFile>
+	</PropertyGroup>
 
-  <ItemGroup>
-    <None Include="..\LICENSE">
-      <Pack>True</Pack>
-      <PackagePath>\</PackagePath>
-    </None>
-    <None Include="..\README.md">
-      <Pack>True</Pack>
-      <PackagePath>\</PackagePath>
-    </None>
-  </ItemGroup>
+	<ItemGroup>
+		<None Include="..\LICENSE">
+			<Pack>True</Pack>
+			<PackagePath>\</PackagePath>
+		</None>
+		<None Include="..\README.md">
+			<Pack>True</Pack>
+			<PackagePath>\</PackagePath>
+		</None>
+	</ItemGroup>
+
+	<ItemGroup>
+		<PackageReference Condition="!$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))" Include="Backport.System.Threading.Lock" Version="3.1.4">
+			<PrivateAssets>all</PrivateAssets>
+			<IncludeAssets>analyzers</IncludeAssets>
+		</PackageReference>
+	</ItemGroup>
 
 </Project>