diff --git a/Sources/Apollo/RequestChainNetworkTransport.swift b/Sources/Apollo/RequestChainNetworkTransport.swift
index 1db56f148e..8a07bff866 100644
--- a/Sources/Apollo/RequestChainNetworkTransport.swift
+++ b/Sources/Apollo/RequestChainNetworkTransport.swift
@@ -69,7 +69,7 @@ open class RequestChainNetworkTransport: NetworkTransport {
                 contextIdentifier: contextIdentifier,
                 clientName: self.clientName,
                 clientVersion: self.clientVersion,
-                additionalHeaders: additionalHeaders,
+                additionalHeaders: self.additionalHeaders,
                 cachePolicy: cachePolicy,
                 autoPersistQueries: self.autoPersistQueries,
                 useGETForQueries: self.useGETForQueries,
@@ -110,16 +110,20 @@ extension RequestChainNetworkTransport: UploadingNetworkTransport {
   /// - Parameters:
   ///   - operation: The operation to create a request for
   ///   - files: The files you wish to upload
+  ///   - manualBoundary: [optional] A manually set boundary for your upload request. Defaults to nil. 
   /// - Returns: The created request.
   open func constructUploadRequest<Operation: GraphQLOperation>(
     for operation: Operation,
-    with files: [GraphQLFile]) -> HTTPRequest<Operation> {
+    with files: [GraphQLFile],
+    manualBoundary: String? = nil) -> HTTPRequest<Operation> {
     
     UploadRequest(graphQLEndpoint: self.endpointURL,
                   operation: operation,
                   clientName: self.clientName,
                   clientVersion: self.clientVersion,
+                  additionalHeaders: self.additionalHeaders,
                   files: files,
+                  manualBoundary: manualBoundary,
                   requestBodyCreator: self.requestBodyCreator)
   }
   
diff --git a/Tests/ApolloTests/UploadTests.swift b/Tests/ApolloTests/UploadTests.swift
index 27c0ac1f20..7bdb704a51 100644
--- a/Tests/ApolloTests/UploadTests.swift
+++ b/Tests/ApolloTests/UploadTests.swift
@@ -12,7 +12,10 @@ class UploadTests: XCTestCase {
     let store = ApolloStore()
     let provider = LegacyInterceptorProvider(store: store)
     let transport = RequestChainNetworkTransport(interceptorProvider: provider,
-                                                 endpointURL: self.uploadClientURL)
+                                                 endpointURL: self.uploadClientURL,
+                                                 additionalHeaders: ["headerKey": "headerValue"])
+    transport.clientName = "test"
+    transport.clientVersion = "test"
     
     return ApolloClient(networkTransport: transport, store: store)
   }()
@@ -295,12 +298,17 @@ class UploadTests: XCTestCase {
                                     mimeType: "text/plain",
                                     fileURL: alphaFileUrl)
     let operation = UploadOneFileMutation(file: alphaFile.originalName)
-    let uploadRequest = UploadRequest(graphQLEndpoint: TestURL.mockServer.url,
-                                      operation: operation,
-                                      clientName: "test",
-                                      clientVersion: "test",
-                                      files: [alphaFile],
-                                      manualBoundary: "TEST.BOUNDARY")
+    
+    let transport = try XCTUnwrap(self.client.networkTransport as? RequestChainNetworkTransport)
+    
+    let httpRequest = transport.constructUploadRequest(for: operation,
+                                                       with: [alphaFile],
+                                                       manualBoundary: "TEST.BOUNDARY")
+    let uploadRequest = try XCTUnwrap(httpRequest as? UploadRequest)
+    
+    let urlRequest = try uploadRequest.toURLRequest()
+    XCTAssertEqual(urlRequest.allHTTPHeaderFields?["headerKey"], "headerValue")
+    
     let formData = try uploadRequest.requestMultipartFormData()
     let stringToCompare = try formData.toTestString()
     
@@ -340,12 +348,16 @@ Alpha file content.
     
     let files = [alphaFile, betaFile]
     let operation = UploadMultipleFilesToTheSameParameterMutation(files: files.map { $0.originalName })
-    let uploadRequest = UploadRequest(graphQLEndpoint: TestURL.mockServer.url,
-                                      operation: operation,
-                                      clientName: "test",
-                                      clientVersion: "test",
-                                      files: files,
-                                      manualBoundary: "TEST.BOUNDARY")
+    let transport = try XCTUnwrap(self.client.networkTransport as? RequestChainNetworkTransport)
+    
+    let httpRequest = transport.constructUploadRequest(for: operation,
+                                                       with: [alphaFile, betaFile],
+                                                       manualBoundary: "TEST.BOUNDARY")
+    let uploadRequest = try XCTUnwrap(httpRequest as? UploadRequest)
+    
+    let urlRequest = try uploadRequest.toURLRequest()
+    XCTAssertEqual(urlRequest.allHTTPHeaderFields?["headerKey"], "headerValue")
+    
     let multipartData = try uploadRequest.requestMultipartFormData()
     let stringToCompare = try multipartData.toTestString()
     
@@ -394,12 +406,15 @@ Bravo file content.
                                       mimeType: "text/plain",
                                       fileURL: charlieFileUrl)
     
-    let uploadRequest = UploadRequest(graphQLEndpoint: TestURL.mockServer.url,
-                                      operation:  HeroNameQuery(),
-                                      clientName: "test",
-                                      clientVersion: "test",
-                                      files: [alphaFile, betaFile, charlieFile],
-                                      manualBoundary: "TEST.BOUNDARY")
+    let transport = try XCTUnwrap(self.client.networkTransport as? RequestChainNetworkTransport)
+    
+    let httpRequest = transport.constructUploadRequest(for: HeroNameQuery(),
+                                                       with: [alphaFile, betaFile, charlieFile],
+                                                       manualBoundary: "TEST.BOUNDARY")
+    let uploadRequest = try XCTUnwrap(httpRequest as? UploadRequest)
+    
+    let urlRequest = try uploadRequest.toURLRequest()
+    XCTAssertEqual(urlRequest.allHTTPHeaderFields?["headerKey"], "headerValue")
     
     let multipartData = try uploadRequest.requestMultipartFormData()
     let stringToCompare = try multipartData.toTestString()