diff --git a/libraries/hfm/src/hfm/HFMFormatRegistry.cpp b/libraries/hfm/src/hfm/HFMFormatRegistry.cpp
index 2a537af151..1125486f5e 100644
--- a/libraries/hfm/src/hfm/HFMFormatRegistry.cpp
+++ b/libraries/hfm/src/hfm/HFMFormatRegistry.cpp
@@ -45,12 +45,12 @@ std::shared_ptr<Serializer> FormatRegistry::getSerializerForMIMETypeID(FormatReg
     return std::shared_ptr<Serializer>();
 }
 
-std::shared_ptr<Serializer> FormatRegistry::getSerializerForMIMEType(const hifi::ByteArray& data, const hifi::VariantHash& mapping, const hifi::URL& url, const std::string& webMediaType) const {
+std::shared_ptr<Serializer> FormatRegistry::getSerializerForMIMEType(const hifi::ByteArray& data, const hifi::URL& url, const std::string& webMediaType) const {
     MIMETypeID id;
     {
         // TODO: shared_lock in C++14
         std::lock_guard<std::mutex> lock(*const_cast<std::mutex*>(&_libraryLock));
-        id = _mimeTypeLibrary.findMatchingMIMEType(data, mapping, url, webMediaType);
+        id = _mimeTypeLibrary.findMatchingMIMEType(data, url, webMediaType);
     }
     return getSerializerForMIMETypeID(id);
 }
diff --git a/libraries/hfm/src/hfm/HFMFormatRegistry.h b/libraries/hfm/src/hfm/HFMFormatRegistry.h
index 6a16dce0b9..bf67254c39 100644
--- a/libraries/hfm/src/hfm/HFMFormatRegistry.h
+++ b/libraries/hfm/src/hfm/HFMFormatRegistry.h
@@ -26,7 +26,7 @@ public:
     MIMETypeID registerMIMEType(const MIMEType& mimeType, std::unique_ptr<Serializer::Factory>& supportedFactory);
     void unregisterMIMEType(const MIMETypeID& id);
 
-    std::shared_ptr<Serializer> getSerializerForMIMEType(const hifi::ByteArray& data, const hifi::VariantHash& mapping, const hifi::URL& url, const std::string& webMediaType) const;
+    std::shared_ptr<Serializer> getSerializerForMIMEType(const hifi::ByteArray& data, const hifi::URL& url, const std::string& webMediaType) const;
     std::shared_ptr<Serializer> getSerializerForMIMETypeID(MIMETypeID id) const;
 
 protected:
diff --git a/libraries/model-networking/src/model-networking/ModelLoader.cpp b/libraries/model-networking/src/model-networking/ModelLoader.cpp
index 51d2c96ee3..a69559ad38 100644
--- a/libraries/model-networking/src/model-networking/ModelLoader.cpp
+++ b/libraries/model-networking/src/model-networking/ModelLoader.cpp
@@ -16,7 +16,7 @@
 
 
 hfm::Model::Pointer ModelLoader::load(const hifi::ByteArray& data, const hifi::VariantHash& mapping, const hifi::URL& url, const std::string& webMediaType) const {
-    auto serializer = DependencyManager::get<ModelFormatRegistry>()->getSerializerForMIMEType(data, mapping, url, webMediaType);
+    auto serializer = DependencyManager::get<ModelFormatRegistry>()->getSerializerForMIMEType(data, url, webMediaType);
     if (!serializer) {
         return hfm::Model::Pointer();
     }
diff --git a/libraries/shared/src/shared/MIMETypeLibrary.cpp b/libraries/shared/src/shared/MIMETypeLibrary.cpp
index 3532876b67..7bc9defab6 100644
--- a/libraries/shared/src/shared/MIMETypeLibrary.cpp
+++ b/libraries/shared/src/shared/MIMETypeLibrary.cpp
@@ -35,7 +35,7 @@ MIMEType MIMETypeLibrary::getMIMEType(const MIMETypeLibrary::ID& id) const {
     return MIMEType::NONE;
 }
 
-MIMETypeLibrary::ID MIMETypeLibrary::findMatchingMIMEType(const hifi::ByteArray& data, const hifi::VariantHash& mapping, const hifi::URL& url, const std::string& webMediaType) const {
+MIMETypeLibrary::ID MIMETypeLibrary::findMatchingMIMEType(const hifi::ByteArray& data, const hifi::URL& url, const std::string& webMediaType) const {
     // Check file contents
     for (auto& mimeType : _mimeTypes) {
         for (auto& fileSignature : mimeType.mimeType.fileSignatures) {
diff --git a/libraries/shared/src/shared/MIMETypeLibrary.h b/libraries/shared/src/shared/MIMETypeLibrary.h
index 354192dd48..94dba0b3c8 100644
--- a/libraries/shared/src/shared/MIMETypeLibrary.h
+++ b/libraries/shared/src/shared/MIMETypeLibrary.h
@@ -68,7 +68,7 @@ public:
     void unregisterMIMEType(const ID& id);
 
     MIMEType getMIMEType(const ID& id) const;
-    ID findMatchingMIMEType(const hifi::ByteArray& data, const hifi::VariantHash& mapping, const hifi::URL& url, const std::string& webMediaType) const;
+    ID findMatchingMIMEType(const hifi::ByteArray& data, const hifi::URL& url, const std::string& webMediaType) const;
 
 protected:
     ID nextID { 1 };