diff --git a/SwiftyTimer.xcodeproj/project.pbxproj b/SwiftyTimer.xcodeproj/project.pbxproj
index 70f8d1b..ba8f175 100644
--- a/SwiftyTimer.xcodeproj/project.pbxproj
+++ b/SwiftyTimer.xcodeproj/project.pbxproj
@@ -205,21 +205,24 @@
 		3E721AB21BF7255C008AF027 /* Project object */ = {
 			isa = PBXProject;
 			attributes = {
-				LastUpgradeCheck = 0800;
+				LastUpgradeCheck = 0900;
 				ORGANIZATIONNAME = "Radosław Pietruszewski";
 				TargetAttributes = {
 					3E721ABA1BF7255D008AF027 = {
 						CreatedOnToolsVersion = 7.1;
-						LastSwiftMigration = 0800;
+						LastSwiftMigration = 0900;
 					};
 					6E7E40891C84B1A20030CEBB = {
 						CreatedOnToolsVersion = 7.2;
+						LastSwiftMigration = 0900;
 					};
 					6E7E40991C84B3790030CEBB = {
 						CreatedOnToolsVersion = 7.2;
+						LastSwiftMigration = 0900;
 					};
 					6E7E40A71C84B4240030CEBB = {
 						CreatedOnToolsVersion = 7.2;
+						LastSwiftMigration = 0900;
 					};
 				};
 			};
@@ -318,14 +321,20 @@
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
@@ -370,14 +379,20 @@
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
@@ -425,6 +440,8 @@
 				PRODUCT_BUNDLE_IDENTIFIER = io.radex.SwiftyTimer;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
+				SWIFT_SWIFT3_OBJC_INFERENCE = Default;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Debug;
 		};
@@ -445,6 +462,8 @@
 				PRODUCT_BUNDLE_IDENTIFIER = io.radex.SwiftyTimer;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
+				SWIFT_SWIFT3_OBJC_INFERENCE = Default;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Release;
 		};
@@ -467,6 +486,8 @@
 				PRODUCT_NAME = SwiftyTimer;
 				SDKROOT = macosx;
 				SKIP_INSTALL = YES;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Debug;
 		};
@@ -489,6 +510,8 @@
 				PRODUCT_NAME = SwiftyTimer;
 				SDKROOT = macosx;
 				SKIP_INSTALL = YES;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Release;
 		};
@@ -508,6 +531,8 @@
 				PRODUCT_NAME = SwiftyTimer;
 				SDKROOT = appletvos;
 				SKIP_INSTALL = YES;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 				TARGETED_DEVICE_FAMILY = 3;
 				TVOS_DEPLOYMENT_TARGET = 9.0;
 			};
@@ -529,6 +554,8 @@
 				PRODUCT_NAME = SwiftyTimer;
 				SDKROOT = appletvos;
 				SKIP_INSTALL = YES;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 				TARGETED_DEVICE_FAMILY = 3;
 				TVOS_DEPLOYMENT_TARGET = 9.0;
 			};
@@ -550,6 +577,8 @@
 				PRODUCT_NAME = SwiftyTimer;
 				SDKROOT = watchos;
 				SKIP_INSTALL = YES;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 				TARGETED_DEVICE_FAMILY = 4;
 				WATCHOS_DEPLOYMENT_TARGET = 2.0;
 			};
@@ -571,6 +600,8 @@
 				PRODUCT_NAME = SwiftyTimer;
 				SDKROOT = watchos;
 				SKIP_INSTALL = YES;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 				TARGETED_DEVICE_FAMILY = 4;
 				WATCHOS_DEPLOYMENT_TARGET = 2.0;
 			};
diff --git a/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer OS X.xcscheme b/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer OS X.xcscheme
index fd51c27..0df0f93 100644
--- a/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer OS X.xcscheme	
+++ b/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer OS X.xcscheme	
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0800"
+   LastUpgradeVersion = "0900"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -26,6 +26,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
       </Testables>
@@ -36,6 +37,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer tvOS.xcscheme b/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer tvOS.xcscheme
index 036a2ac..2b21ca6 100644
--- a/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer tvOS.xcscheme	
+++ b/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer tvOS.xcscheme	
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0800"
+   LastUpgradeVersion = "0900"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -26,6 +26,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
       </Testables>
@@ -36,6 +37,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer watchOS.xcscheme b/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer watchOS.xcscheme
index 31dc3e3..a329e78 100644
--- a/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer watchOS.xcscheme	
+++ b/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer watchOS.xcscheme	
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0800"
+   LastUpgradeVersion = "0900"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -26,6 +26,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
       </Testables>
@@ -36,6 +37,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer.xcscheme b/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer.xcscheme
index 897a69b..b05d922 100644
--- a/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer.xcscheme
+++ b/SwiftyTimer.xcodeproj/xcshareddata/xcschemes/SwiftyTimer.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0800"
+   LastUpgradeVersion = "0900"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -26,6 +26,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
       </Testables>
@@ -36,6 +37,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"