diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 00000000..ddb6be73
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,3 @@
+## 2.2.1
+
+* Updated for Swift 4.1.
diff --git a/Graph.podspec b/Graph.podspec
index d6dbfed8..67a7510e 100755
--- a/Graph.podspec
+++ b/Graph.podspec
@@ -1,6 +1,7 @@
 Pod::Spec.new do |s|
     s.name = 'Graph'
-    s.version = '2.2.0'
+    s.version = '2.2.1'
+    s.swift_version = '4.0'
     s.license = 'BSD-3-Clause'
     s.summary = 'Graph is a semantic database that is used to create data-driven applications.'
     s.homepage = 'http://graphswift.io'
diff --git a/Graph.xcodeproj/project.pbxproj b/Graph.xcodeproj/project.pbxproj
index dfb65fb1..7cba8732 100644
--- a/Graph.xcodeproj/project.pbxproj
+++ b/Graph.xcodeproj/project.pbxproj
@@ -642,7 +642,7 @@
 			isa = PBXProject;
 			attributes = {
 				LastSwiftUpdateCheck = 0800;
-				LastUpgradeCheck = 0900;
+				LastUpgradeCheck = 0930;
 				ORGANIZATIONNAME = "Daniel Dahan";
 				TargetAttributes = {
 					96E3C3A81D3AB41F0086A024 = {
@@ -887,6 +887,7 @@
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
 				CLANG_WARN_EMPTY_BODY = YES;
@@ -894,6 +895,7 @@
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
@@ -949,6 +951,7 @@
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
 				CLANG_WARN_EMPTY_BODY = YES;
@@ -956,6 +959,7 @@
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
diff --git a/Graph.xcodeproj/xcshareddata/xcschemes/Graph iOS.xcscheme b/Graph.xcodeproj/xcshareddata/xcschemes/Graph iOS.xcscheme
index 8adcb180..c8e7878a 100644
--- a/Graph.xcodeproj/xcshareddata/xcschemes/Graph iOS.xcscheme	
+++ b/Graph.xcodeproj/xcshareddata/xcschemes/Graph iOS.xcscheme	
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0920"
+   LastUpgradeVersion = "0940"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -26,7 +26,6 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
          <TestableReference
@@ -56,7 +55,6 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/Graph.xcodeproj/xcshareddata/xcschemes/Graph macOS.xcscheme b/Graph.xcodeproj/xcshareddata/xcschemes/Graph macOS.xcscheme
index 461ea5d6..7aecffdd 100644
--- a/Graph.xcodeproj/xcshareddata/xcschemes/Graph macOS.xcscheme	
+++ b/Graph.xcodeproj/xcshareddata/xcschemes/Graph macOS.xcscheme	
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0920"
+   LastUpgradeVersion = "0940"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -26,7 +26,6 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
          <TestableReference
@@ -56,7 +55,6 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/Sources/Info.plist b/Sources/Info.plist
index a60ea4a4..51c40676 100644
--- a/Sources/Info.plist
+++ b/Sources/Info.plist
@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>2.2.0</string>
+	<string>2.2.1</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
diff --git a/Tests/GraphTests.swift b/Tests/GraphTests.swift
index 8e9f6270..6a773f2a 100644
--- a/Tests/GraphTests.swift
+++ b/Tests/GraphTests.swift
@@ -5,16 +5,16 @@
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
- *  *  Redistributions of source code must retain the above copyright notice, this
- *    list of conditions and the following disclaimer.
+ *    * Redistributions of source code must retain the above copyright notice, this
+ *      list of conditions and the following disclaimer.
  *
- *  *  Redistributions in binary form must reproduce the above copyright notice,
- *    this list of conditions and the following disclaimer in the documentation
- *    and/or other materials provided with the distribution.
+ *    * Redistributions in binary form must reproduce the above copyright notice,
+ *      this list of conditions and the following disclaimer in the documentation
+ *      and/or other materials provided with the distribution.
  *
- *  *  Neither the name of CosmicMind nor the names of its
- *    contributors may be used to endorse or promote products derived from
- *    this software without specific prior written permission.
+ *    * Neither the name of CosmicMind nor the names of its
+ *      contributors may be used to endorse or promote products derived from
+ *      this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE