diff --git a/BitFaster.Caching/BitFaster.Caching.csproj b/BitFaster.Caching/BitFaster.Caching.csproj
index 8c928cd8..68a81b1c 100644
--- a/BitFaster.Caching/BitFaster.Caching.csproj
+++ b/BitFaster.Caching/BitFaster.Caching.csproj
@@ -22,6 +22,8 @@
     <SymbolPackageFormat>snupkg</SymbolPackageFormat>
     <AssemblyVersion>1.0.7.0</AssemblyVersion>
     <FileVersion>1.0.7.0</FileVersion>
+    <EnablePackageValidation>true</EnablePackageValidation>
+    <PackageValidationBaselineVersion>1.0.3</PackageValidationBaselineVersion>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(GITHUB_ACTIONS)' == 'true'">
diff --git a/BitFaster.Caching/ICache.cs b/BitFaster.Caching/ICache.cs
index 245d4e65..315447dc 100644
--- a/BitFaster.Caching/ICache.cs
+++ b/BitFaster.Caching/ICache.cs
@@ -63,9 +63,11 @@ public interface ICache<K, V>
         /// <param name="value">The new value.</param>
         void AddOrUpdate(K key, V value);
 
+#if NETCOREAPP3_0_OR_GREATER
         /// <summary>
         /// Removes all keys and values from the cache.
         /// </summary>
-        void Clear();
+        void Clear() { }
+#endif
     }
 }
diff --git a/BitFaster.Caching/Lifetime.cs b/BitFaster.Caching/Lifetime.cs
index 378d3eea..74ebf899 100644
--- a/BitFaster.Caching/Lifetime.cs
+++ b/BitFaster.Caching/Lifetime.cs
@@ -9,7 +9,7 @@ namespace BitFaster.Caching
     /// lifetime is disposed.
     /// </summary>
     /// <typeparam name="T">The type of value</typeparam>
-    public sealed class Lifetime<T> : IDisposable
+    public class Lifetime<T> : IDisposable
     {
         private readonly Action onDisposeAction;
         private readonly ReferenceCount<T> refCount;
diff --git a/BitFaster.Caching/Scoped.cs b/BitFaster.Caching/Scoped.cs
index dad6ee46..6379e442 100644
--- a/BitFaster.Caching/Scoped.cs
+++ b/BitFaster.Caching/Scoped.cs
@@ -11,7 +11,7 @@ namespace BitFaster.Caching
     /// the wrapped object from being diposed until the calling code completes.
     /// </summary>
     /// <typeparam name="T">The type of scoped value.</typeparam>
-    public sealed class Scoped<T> : IDisposable where T : IDisposable
+    public class Scoped<T> : IDisposable where T : IDisposable
     {
         private ReferenceCount<T> refCount;
         private bool isDisposed;