diff --git a/Classes/GPXRoot.swift b/Classes/GPXRoot.swift
index 1f21c72..f1f2c88 100644
--- a/Classes/GPXRoot.swift
+++ b/Classes/GPXRoot.swift
@@ -44,11 +44,11 @@ public final class GPXRoot: GPXElement, Codable {
     // MARK: GPX v1.1 Namespaces
     
     /// Link to the GPX v1.1 schema
-    private let schema = "http://www.topografix.com/GPX/1/1"
+    private var schema = "http://www.topografix.com/GPX/1/1"
     /// Link to the schema locations. If extended, the extended schema should be added.
     private var schemaLocation = "http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd"
     /// Link to XML schema instance
-    private let xsi = "http://www.w3.org/2001/XMLSchema-instance"
+    private var xsi = "http://www.w3.org/2001/XMLSchema-instance"
     /// For if GPX file is extended, and contains extra attributes on gpx main tag.
     private var extensionAttributes: [String : String]?
     
diff --git a/Example/CoreGPX.xcodeproj/project.pbxproj b/Example/CoreGPX.xcodeproj/project.pbxproj
index 28e75ac..43b447c 100644
--- a/Example/CoreGPX.xcodeproj/project.pbxproj
+++ b/Example/CoreGPX.xcodeproj/project.pbxproj
@@ -223,7 +223,7 @@
 			isa = PBXProject;
 			attributes = {
 				LastSwiftUpdateCheck = 0830;
-				LastUpgradeCheck = 1020;
+				LastUpgradeCheck = 1200;
 				ORGANIZATIONNAME = Vincent;
 				TargetAttributes = {
 					607FACCF1AFB9204008FA782 = {
@@ -410,6 +410,7 @@
 				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_QUOTED_INCLUDE_IN_FRAMEWORK_HEADER = YES;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
 				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
@@ -435,7 +436,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				MTL_ENABLE_DEBUG_INFO = YES;
 				ONLY_ACTIVE_ARCH = YES;
 				SDKROOT = iphoneos;
@@ -466,6 +467,7 @@
 				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_QUOTED_INCLUDE_IN_FRAMEWORK_HEADER = YES;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
 				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
@@ -484,7 +486,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				SDKROOT = iphoneos;
 				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";
diff --git a/Example/CoreGPX.xcodeproj/xcshareddata/xcschemes/CoreGPX Tests.xcscheme b/Example/CoreGPX.xcodeproj/xcshareddata/xcschemes/CoreGPX Tests.xcscheme
index 5164733..cc149b6 100644
--- a/Example/CoreGPX.xcodeproj/xcshareddata/xcschemes/CoreGPX Tests.xcscheme	
+++ b/Example/CoreGPX.xcodeproj/xcshareddata/xcschemes/CoreGPX Tests.xcscheme	
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1020"
+   LastUpgradeVersion = "1200"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -23,8 +23,6 @@
             </BuildableReference>
          </TestableReference>
       </Testables>
-      <AdditionalOptions>
-      </AdditionalOptions>
    </TestAction>
    <LaunchAction
       buildConfiguration = "Debug"
@@ -36,8 +34,6 @@
       debugDocumentVersioning = "YES"
       debugServiceExtension = "internal"
       allowLocationSimulation = "YES">
-      <AdditionalOptions>
-      </AdditionalOptions>
    </LaunchAction>
    <ProfileAction
       buildConfiguration = "Release"
diff --git a/Example/CoreGPX.xcodeproj/xcshareddata/xcschemes/CoreGPX-Example.xcscheme b/Example/CoreGPX.xcodeproj/xcshareddata/xcschemes/CoreGPX-Example.xcscheme
index a7018fb..8289ea4 100644
--- a/Example/CoreGPX.xcodeproj/xcshareddata/xcschemes/CoreGPX-Example.xcscheme
+++ b/Example/CoreGPX.xcodeproj/xcshareddata/xcschemes/CoreGPX-Example.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1020"
+   LastUpgradeVersion = "1200"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
diff --git a/Example/Pods/Pods.xcodeproj/project.pbxproj b/Example/Pods/Pods.xcodeproj/project.pbxproj
index 6a4ec57..8664eac 100644
--- a/Example/Pods/Pods.xcodeproj/project.pbxproj
+++ b/Example/Pods/Pods.xcodeproj/project.pbxproj
@@ -606,7 +606,7 @@
 			isa = PBXProject;
 			attributes = {
 				LastSwiftUpdateCheck = 1010;
-				LastUpgradeCheck = 1020;
+				LastUpgradeCheck = 1200;
 				TargetAttributes = {
 					1FF6BE2AF737A7CF5E77D983FE99CC8E = {
 						LastSwiftMigration = 1020;
@@ -838,7 +838,7 @@
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
 				INFOPLIST_FILE = "Target Support Files/Pods-CoreGPX_Tests/Info.plist";
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
-				IPHONEOS_DEPLOYMENT_TARGET = 9.3;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				MACH_O_TYPE = staticlib;
 				MODULEMAP_FILE = "Target Support Files/Pods-CoreGPX_Tests/Pods-CoreGPX_Tests.modulemap";
@@ -871,7 +871,7 @@
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
 				INFOPLIST_FILE = "Target Support Files/Pods-CoreGPX_Tests/Info.plist";
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
-				IPHONEOS_DEPLOYMENT_TARGET = 9.3;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				MACH_O_TYPE = staticlib;
 				MODULEMAP_FILE = "Target Support Files/Pods-CoreGPX_Tests/Pods-CoreGPX_Tests.modulemap";
@@ -905,13 +905,15 @@
 				GCC_PREFIX_HEADER = "Target Support Files/CoreGPX/CoreGPX-prefix.pch";
 				INFOPLIST_FILE = "Target Support Files/CoreGPX/Info.plist";
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
-				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
+				MARKETING_VERSION = 0.8.1;
 				MODULEMAP_FILE = "Target Support Files/CoreGPX/CoreGPX.modulemap";
 				PRODUCT_MODULE_NAME = CoreGPX;
 				PRODUCT_NAME = CoreGPX;
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
+				SUPPORTED_PLATFORMS = "iphonesimulator iphoneos";
 				SWIFT_ACTIVE_COMPILATION_CONDITIONS = "$(inherited) ";
 				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";
 				SWIFT_VERSION = 5.0;
@@ -938,7 +940,7 @@
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
 				INFOPLIST_FILE = "Target Support Files/Pods-CoreGPX_Example/Info.plist";
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
-				IPHONEOS_DEPLOYMENT_TARGET = 9.3;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				MACH_O_TYPE = staticlib;
 				MODULEMAP_FILE = "Target Support Files/Pods-CoreGPX_Example/Pods-CoreGPX_Example.modulemap";
@@ -973,7 +975,7 @@
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
 				INFOPLIST_FILE = "Target Support Files/Pods-CoreGPX_Example/Info.plist";
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
-				IPHONEOS_DEPLOYMENT_TARGET = 9.3;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
 				MACH_O_TYPE = staticlib;
 				MODULEMAP_FILE = "Target Support Files/Pods-CoreGPX_Example/Pods-CoreGPX_Example.modulemap";
@@ -1019,6 +1021,7 @@
 				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_QUOTED_INCLUDE_IN_FRAMEWORK_HEADER = YES;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
 				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
@@ -1046,7 +1049,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				MACOSX_DEPLOYMENT_TARGET = 10.9;
 				MTL_ENABLE_DEBUG_INFO = YES;
 				ONLY_ACTIVE_ARCH = YES;
@@ -1073,8 +1076,9 @@
 				GCC_PREFIX_HEADER = "Target Support Files/CoreGPX/CoreGPX-prefix.pch";
 				INFOPLIST_FILE = "Target Support Files/CoreGPX/Info.plist";
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
-				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
+				MARKETING_VERSION = 0.8.1;
 				MODULEMAP_FILE = "Target Support Files/CoreGPX/CoreGPX.modulemap";
 				PRODUCT_MODULE_NAME = CoreGPX;
 				PRODUCT_NAME = CoreGPX;
@@ -1116,6 +1120,7 @@
 				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_QUOTED_INCLUDE_IN_FRAMEWORK_HEADER = YES;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
 				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
@@ -1140,7 +1145,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				MACOSX_DEPLOYMENT_TARGET = 10.9;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				PRODUCT_NAME = "$(TARGET_NAME)";
diff --git a/Example/Pods/Pods.xcodeproj/xcshareddata/xcschemes/CoreGPX-macOS.xcscheme b/Example/Pods/Pods.xcodeproj/xcshareddata/xcschemes/CoreGPX-macOS.xcscheme
index 1cc04ab..b9ea13b 100644
--- a/Example/Pods/Pods.xcodeproj/xcshareddata/xcschemes/CoreGPX-macOS.xcscheme
+++ b/Example/Pods/Pods.xcodeproj/xcshareddata/xcschemes/CoreGPX-macOS.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1020"
+   LastUpgradeVersion = "1200"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -27,6 +27,15 @@
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       shouldUseLaunchSchemeArgsEnv = "YES">
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "BF5A9E1222088463003A5379"
+            BuildableName = "CoreGPX.framework"
+            BlueprintName = "CoreGPX-macOS"
+            ReferencedContainer = "container:Pods.xcodeproj">
+         </BuildableReference>
+      </MacroExpansion>
       <Testables>
          <TestableReference
             skipped = "NO">
@@ -39,17 +48,6 @@
             </BuildableReference>
          </TestableReference>
       </Testables>
-      <MacroExpansion>
-         <BuildableReference
-            BuildableIdentifier = "primary"
-            BlueprintIdentifier = "BF5A9E1222088463003A5379"
-            BuildableName = "CoreGPX.framework"
-            BlueprintName = "CoreGPX-macOS"
-            ReferencedContainer = "container:Pods.xcodeproj">
-         </BuildableReference>
-      </MacroExpansion>
-      <AdditionalOptions>
-      </AdditionalOptions>
    </TestAction>
    <LaunchAction
       buildConfiguration = "Debug"
@@ -70,8 +68,6 @@
             ReferencedContainer = "container:Pods.xcodeproj">
          </BuildableReference>
       </MacroExpansion>
-      <AdditionalOptions>
-      </AdditionalOptions>
    </LaunchAction>
    <ProfileAction
       buildConfiguration = "Release"
diff --git a/Example/Pods/Pods.xcodeproj/xcshareddata/xcschemes/CoreGPX-watchOS.xcscheme b/Example/Pods/Pods.xcodeproj/xcshareddata/xcschemes/CoreGPX-watchOS.xcscheme
index daf99f2..cb5d3f0 100644
--- a/Example/Pods/Pods.xcodeproj/xcshareddata/xcschemes/CoreGPX-watchOS.xcscheme
+++ b/Example/Pods/Pods.xcodeproj/xcshareddata/xcschemes/CoreGPX-watchOS.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1020"
+   LastUpgradeVersion = "1200"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
diff --git a/Example/Pods/Pods.xcodeproj/xcshareddata/xcschemes/CoreGPX.xcscheme b/Example/Pods/Pods.xcodeproj/xcshareddata/xcschemes/CoreGPX.xcscheme
index 15599d5..ebb6003 100644
--- a/Example/Pods/Pods.xcodeproj/xcshareddata/xcschemes/CoreGPX.xcscheme
+++ b/Example/Pods/Pods.xcodeproj/xcshareddata/xcschemes/CoreGPX.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1020"
+   LastUpgradeVersion = "1200"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
diff --git a/Example/Pods/Target Support Files/CoreGPX/Info.plist b/Example/Pods/Target Support Files/CoreGPX/Info.plist
index dc953ee..1f91650 100644
--- a/Example/Pods/Target Support Files/CoreGPX/Info.plist	
+++ b/Example/Pods/Target Support Files/CoreGPX/Info.plist	
@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>0.5</string>
+	<string>$(MARKETING_VERSION)</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>