diff --git a/gradle.properties b/gradle.properties
index 9b094d6..db9612c 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -4,7 +4,7 @@ apacheTaglibsStandardVersion=1.2.5
 groovyVersion=2.4.15
 javaxServletJspJstlApiVersion=1.2.1
 multithreadedtcVersion=1.01
-pivotalGemFireVersion=9.8.6
+pivotalGemFireVersion=9.9.1
 # The Spring Boot & Spring Session version are the only required version properties.
 # The other Spring version properties are for overriding/testing purposes.
 springVersion=5.2.4.BUILD-SNAPSHOT