diff -r ece620f32d2d -r 6879069d9d94 make/common/SetupJavaCompilers.gmk
--- a/make/common/SetupJavaCompilers.gmk	Thu Dec 13 17:01:15 2018 +0100
+++ b/make/common/SetupJavaCompilers.gmk	Thu Dec 13 19:06:11 2018 +0100
@@ -72,7 +72,7 @@
 $(eval $(call SetupJavaCompiler,GENERATE_JDKBYTECODE, \
     JVM := $(JAVA_JAVAC), \
     JAVAC := $(NEW_JAVAC), \
-    FLAGS := -source 12 -target 12 --doclint-format html5 \
+    FLAGS := -source 13 -target 13 --doclint-format html5 \
         -encoding ascii -XDignore.symbol.file=true $(JAVAC_WARNINGS), \
     SERVER_DIR := $(SJAVAC_SERVER_DIR), \
     SERVER_JVM := $(SJAVAC_SERVER_JAVA)))
@@ -82,7 +82,7 @@
 $(eval $(call SetupJavaCompiler,GENERATE_JDKBYTECODE_NOWARNINGS, \
     JVM := $(JAVA_JAVAC), \
     JAVAC := $(NEW_JAVAC), \
-    FLAGS := -source 12 -target 12 \
+    FLAGS := -source 13 -target 13 \
         -encoding ascii -XDignore.symbol.file=true $(DISABLE_WARNINGS), \
     SERVER_DIR := $(SJAVAC_SERVER_DIR), \
     SERVER_JVM := $(SJAVAC_SERVER_JAVA)))