diff --git a/Cartfile.resolved b/Cartfile.resolved
index 6900f77..16929f1 100644
--- a/Cartfile.resolved
+++ b/Cartfile.resolved
@@ -1 +1 @@
-github "ReactiveX/RxSwift" "3.3.1"
+github "ReactiveX/RxSwift" "4.5.0"
diff --git a/RxCoreMotion.xcodeproj/project.pbxproj b/RxCoreMotion.xcodeproj/project.pbxproj
index 4eccebc..2c39794 100644
--- a/RxCoreMotion.xcodeproj/project.pbxproj
+++ b/RxCoreMotion.xcodeproj/project.pbxproj
@@ -330,7 +330,7 @@
 				SKIP_INSTALL = YES;
 				SWIFT_ACTIVE_COMPILATION_CONDITIONS = DEBUG;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				VERSIONING_SYSTEM = "apple-generic";
 				VERSION_INFO_PREFIX = "";
@@ -361,7 +361,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = rx.swift.RxCoreMotion;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				VERSIONING_SYSTEM = "apple-generic";
 				VERSION_INFO_PREFIX = "";