diff --git a/src/Imageflow.Server.Storage.RemoteReader/RemoteReaderService.cs b/src/Imageflow.Server.Storage.RemoteReader/RemoteReaderService.cs
index b0673ab..deecc74 100644
--- a/src/Imageflow.Server.Storage.RemoteReader/RemoteReaderService.cs
+++ b/src/Imageflow.Server.Storage.RemoteReader/RemoteReaderService.cs
@@ -120,7 +120,7 @@ public bool SupportsPath(string virtualPath)
                 options.IgnorePrefixCase ? StringComparison.OrdinalIgnoreCase : StringComparison.Ordinal));
         }
         
-        private static string SanitizeImageExtension(string extension)
+        private static string? SanitizeImageExtension(string extension)
         {
             //TODO: Deduplicate this function when making Imazen.ImageAPI.Client
             extension = extension.ToLowerInvariant().TrimStart('.');
diff --git a/src/Imageflow.Server.Storage.RemoteReader/RemoteReaderServiceOptions.cs b/src/Imageflow.Server.Storage.RemoteReader/RemoteReaderServiceOptions.cs
index 3229567..9927953 100644
--- a/src/Imageflow.Server.Storage.RemoteReader/RemoteReaderServiceOptions.cs
+++ b/src/Imageflow.Server.Storage.RemoteReader/RemoteReaderServiceOptions.cs
@@ -6,14 +6,14 @@ namespace Imageflow.Server.Storage.RemoteReader
     public class RemoteReaderServiceOptions
     {
         internal readonly List<string> Prefixes = new List<string>();
-        public string SigningKey { get; set; }
+        public required string SigningKey { get; set; }
         
         /// <summary>
         /// Sometimes you need to support multiple signing keys; either for different users or for
         /// phasing out a leaked key. Trying multiple keys during each request adds a bit a processing time;
         /// benchmark performance if you have many.
         /// </summary>
-        public IEnumerable<string> SigningKeys { get; set; }
+        public IEnumerable<string>? SigningKeys { get; set; }
         public bool IgnorePrefixCase { get; set; }
 
         public Func<Uri, string> HttpClientSelector { get; set; } = _ => "";
diff --git a/src/Imazen.HybridCache/AsyncCache.cs b/src/Imazen.HybridCache/AsyncCache.cs
index ddd261c..287177f 100644
--- a/src/Imazen.HybridCache/AsyncCache.cs
+++ b/src/Imazen.HybridCache/AsyncCache.cs
@@ -487,7 +487,7 @@ private static bool IsFileLocked(IOException exception)
         //
         //
 
-        private BlobCacheSupportData SupportData { get; set; }
+        private BlobCacheSupportData? SupportData { get; set; }
         public void Initialize(BlobCacheSupportData supportData)
         {
             SupportData = supportData;
diff --git a/src/Imazen.HybridCache/HybridCache.cs b/src/Imazen.HybridCache/HybridCache.cs
index 2497ba9..4c45223 100644
--- a/src/Imazen.HybridCache/HybridCache.cs
+++ b/src/Imazen.HybridCache/HybridCache.cs
@@ -18,7 +18,7 @@ public class HybridCache : IBlobCache
         private CleanupManager CleanupManager { get; }
         private ICacheDatabase<ICacheDatabaseRecord> Database { get; }
         
-        private BlobCacheSupportData SupportData { get; set; }
+        private BlobCacheSupportData? SupportData { get; set; }
 
         public string UniqueName { get; }
         
diff --git a/tests/ImazenShared.Tests/Routing/Serving/MemoryLogger.cs b/tests/ImazenShared.Tests/Routing/Serving/MemoryLogger.cs
index e9cd037..7b9842c 100644
--- a/tests/ImazenShared.Tests/Routing/Serving/MemoryLogger.cs
+++ b/tests/ImazenShared.Tests/Routing/Serving/MemoryLogger.cs
@@ -29,7 +29,11 @@ public class MemoryLogger(string categoryName, Func<string, LogLevel, bool>? fil
 
     private static readonly AsyncLocal<Stack<object>> Scopes = new AsyncLocal<Stack<object>>();
 
-    public IDisposable BeginScope<TState>(TState state)  
+    public IDisposable BeginScope<TState>(TState state)
+#if DOTNET8_0_OR_GREATER
+        where TState : notnull
+#endif 
+    where TState : notnull
     {
         if (state == null)
             throw new ArgumentNullException(nameof(state));