diff --git a/tools/jack b/tools/jack
index 8460b54..256926b 100755
--- a/tools/jack
+++ b/tools/jack
@@ -22,7 +22,7 @@
 #
 # Settings
 #
-JACK_VERSION=${JACK_VERSION:=3.30.BETA}
+JACK_VERSION=${JACK_VERSION:=3.31.BETA}
 JACK_HOME="${JACK_HOME:=$HOME/.jack-server}"
 CLIENT_SETTING="${CLIENT_SETTING:=$HOME/.jack-settings}"
 TMPDIR=${TMPDIR:=/tmp}
diff --git a/tools/jack-jacoco-reporter.jar b/tools/jack-jacoco-reporter.jar
index 23a88b5..f769e27 100644
--- a/tools/jack-jacoco-reporter.jar
+++ b/tools/jack-jacoco-reporter.jar
Binary files differ
diff --git a/tools/jack_versions.mk b/tools/jack_versions.mk
index 6dfda4b..e00fc02 100644
--- a/tools/jack_versions.mk
+++ b/tools/jack_versions.mk
@@ -18,10 +18,10 @@
 jack_jar_tools := $(LOCAL_PATH)/jack-jar-tools.jar
 jack_eng_jar := $(LOCAL_PATH)/jacks/jack.jar
 
-JACK_STABLE_VERSION := 3.30.BETA
+JACK_STABLE_VERSION := 3.31.BETA
 JACK_DOGFOOD_VERSION := 4.1.PRE_ALPHA
-JACK_SDKTOOL_VERSION := 3.30.BETA
-JACK_LANG_DEV_VERSION := 3.30.BETA
+JACK_SDKTOOL_VERSION := 3.31.BETA
+JACK_LANG_DEV_VERSION := 3.31.BETA
 ifneq ("$(wildcard $(jack_eng_jar))","")
 JACK_ENGINEERING_VERSION := $(shell java -jar $(jack_jar_tools) --version-code jack $(jack_eng_jar))
 endif
diff --git a/tools/jacks/jack-3.30.BETA.jar b/tools/jacks/jack-3.31.BETA.jar
similarity index 91%
rename from tools/jacks/jack-3.30.BETA.jar
rename to tools/jacks/jack-3.31.BETA.jar
index 2424c44..b63ec67 100644
--- a/tools/jacks/jack-3.30.BETA.jar
+++ b/tools/jacks/jack-3.31.BETA.jar
Binary files differ
diff --git a/tools/jills/jill-3.30.BETA.jar b/tools/jills/jill-3.31.BETA.jar
similarity index 93%
rename from tools/jills/jill-3.30.BETA.jar
rename to tools/jills/jill-3.31.BETA.jar
index 06e5895..fc3f82d 100644
--- a/tools/jills/jill-3.30.BETA.jar
+++ b/tools/jills/jill-3.31.BETA.jar
Binary files differ