diff --git a/CJavaVM.xcodeproj/project.pbxproj b/CJavaVM.xcodeproj/project.pbxproj
index 78082ae..45210fb 100644
--- a/CJavaVM.xcodeproj/project.pbxproj
+++ b/CJavaVM.xcodeproj/project.pbxproj
@@ -100,7 +100,7 @@
 		BBC13E411D4994F20035A039 /* Project object */ = {
 			isa = PBXProject;
 			attributes = {
-				LastUpgradeCheck = 0900;
+				LastUpgradeCheck = 0930;
 				ORGANIZATIONNAME = "John Holdsworth";
 				TargetAttributes = {
 					BBC13E491D4994F20035A039 = {
@@ -162,6 +162,7 @@
 				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;
@@ -169,6 +170,7 @@
 				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;
@@ -220,6 +222,7 @@
 				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;
@@ -227,6 +230,7 @@
 				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/Package.swift b/Package.swift
index 6a9495c..f1e828c 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,3 +1,4 @@
+// swift-tools-version:5.0
 
 import PackageDescription
 
diff --git a/xcode.modulemap b/xcode.modulemap
index 2bcd3b0..c097686 100644
--- a/xcode.modulemap
+++ b/xcode.modulemap
@@ -1,5 +1,5 @@
 
 module CJavaVM [system] {
-    header "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.13.sdk/System/Library/Frameworks/JavaVM.framework/Versions/A/Headers/jni.h"
+    header "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/JavaVM.framework/Versions/A/Headers/jni.h"
     export *
 }