diff --git a/src/IIIF/IIIF/IIIF.csproj b/src/IIIF/IIIF/IIIF.csproj
index d8cb475..93df607 100644
--- a/src/IIIF/IIIF/IIIF.csproj
+++ b/src/IIIF/IIIF/IIIF.csproj
@@ -3,6 +3,7 @@
     <PropertyGroup>
         <TargetFramework>net6.0</TargetFramework>
         <PackageId>iiif-net</PackageId>
+        <LangVersion>10.0</LangVersion>
         <Authors>Donald Gray,Tom Crane</Authors>
         <Company>Digirati</Company>
         <Description>IIIF Library for .NET Core</Description>
diff --git a/src/IIIF/IIIF/Serialisation/Deserialisation/ResourceBaseV3Converter.cs b/src/IIIF/IIIF/Serialisation/Deserialisation/ResourceBaseV3Converter.cs
index c9f03fb..1c49518 100644
--- a/src/IIIF/IIIF/Serialisation/Deserialisation/ResourceBaseV3Converter.cs
+++ b/src/IIIF/IIIF/Serialisation/Deserialisation/ResourceBaseV3Converter.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using IIIF.Auth.V2;
 using IIIF.ImageApi.V3;
 using IIIF.Presentation.V3;
@@ -20,13 +21,13 @@ public class ResourceBaseV3Converter : ReadOnlyConverter<ResourceBase>
     {
         var jsonObject = JObject.Load(reader);
 
-        var resourceBase = IdentifyConcreteType(jsonObject);
+        var resourceBase = IdentifyConcreteType(jsonObject, serializer);
 
         serializer.Populate(jsonObject.CreateReader(), resourceBase);
         return resourceBase;
     }
 
-    private static ResourceBase? IdentifyConcreteType(JObject jsonObject)
+    private static ResourceBase? IdentifyConcreteType(JObject jsonObject, JsonSerializer serializer)
     {
         ResourceBase? resourceBase = null;
         if (!jsonObject.ContainsKey("type"))
@@ -54,7 +55,7 @@ public class ResourceBaseV3Converter : ReadOnlyConverter<ResourceBase>
             nameof(TextualBody) => new TextualBody(jsonObject["value"].Value<string>()),
             _ => null
         };
-
+        
         if (resourceBase != null) return resourceBase;
 
         if (jsonObject.ContainsKey("motivation"))
@@ -68,6 +69,14 @@ public class ResourceBaseV3Converter : ReadOnlyConverter<ResourceBase>
                 _ => new UnknownMotivation(motivation)
             };
         }
+        
+        // Look for consumer-provided mapping
+        if (type != null
+            && serializer.Context.Context is IDictionary<string, Func<JObject, ResourceBase>> customMappings
+            && customMappings.TryGetValue(type, out var customMapping))
+        {
+            resourceBase = customMapping(jsonObject);
+        }
 
         if (resourceBase == null) return new ExternalResource(type);
 
diff --git a/src/IIIF/IIIF/Serialisation/IIIFSerialiserX.cs b/src/IIIF/IIIF/Serialisation/IIIFSerialiserX.cs
index 9358a6d..de05029 100644
--- a/src/IIIF/IIIF/Serialisation/IIIFSerialiserX.cs
+++ b/src/IIIF/IIIF/Serialisation/IIIFSerialiserX.cs
@@ -10,7 +10,7 @@ namespace IIIF.Serialisation;
 /// </summary>
 public static class IIIFSerialiserX
 {
-    private static readonly JsonSerializerSettings SerializerSettings = new()
+    public static JsonSerializerSettings SerializerSettings { get; set; } = new()
     {
         NullValueHandling = NullValueHandling.Ignore,
         ContractResolver = new PrettyIIIFContractResolver(),
@@ -23,16 +23,17 @@ public static class IIIFSerialiserX
         }
     };
 
-    private static readonly JsonSerializerSettings DeserializerSettings = new()
+    public static JsonSerializerSettings DeserializerSettings { get; set; } = new()
     {
         NullValueHandling = NullValueHandling.Ignore,
         ContractResolver = new PrettyIIIFContractResolver(),
         Formatting = Formatting.Indented,
         Converters = new List<JsonConverter>
         {
-            new ImageService2Converter(), new AnnotationV3Converter(), new ResourceBaseV3Converter(),
-            new StructuralLocationConverter(), new ExternalResourceConverter(), new PaintableConverter(),
-            new SelectorConverter(), new ServiceConverter(), new ResourceConverter(), new CollectionItemConverter()
+            new ExternalResourceConverter(), new ImageService2Converter(), new AnnotationV3Converter(),
+            new StructuralLocationConverter(), new PaintableConverter(),
+            new SelectorConverter(), new ResourceBaseV3Converter(),  new ServiceConverter(),
+            new CollectionItemConverter(), new ResourceConverter()
         }
     };