diff --git a/com.ibm.wala.cast.test/build.gradle b/com.ibm.wala.cast.test/build.gradle
index 7a1021996..7229c6cf8 100644
--- a/com.ibm.wala.cast.test/build.gradle
+++ b/com.ibm.wala.cast.test/build.gradle
@@ -97,7 +97,7 @@ model {
 	tasks.test {
 		def lib = linkXlator_testSharedLibrary
 		dependsOn lib
-		systemProperty 'java.library.path', lib.destinationDir
+		systemProperty 'java.library.path', lib.destinationDirectory.orNull.asFile
 
 		// TODO: compute path on following line from 'cast' library properties somehow
 		def castLibDir = "${project(':com.ibm.wala.cast').buildDir}/libs/cast/shared"
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index a5fe1cb94..91ca28c8b 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index ea720f986..16d28051c 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.7-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.6-bin.zip