diff --git a/Makefile b/Makefile
index c139cac..3892367 100644
--- a/Makefile
+++ b/Makefile
@@ -19,6 +19,7 @@ endif
 ifeq ($(shell uname -s),SunOS)
     PG_CPPFLAGS += -Wno-sign-compare -D__EXTENSIONS__
 endif
+PG_CPPFLAGS += -DPG_CRON_VERSION=$(shell sed -r -n -e '1s/.* v([^ ]*) .*/\1/p' <CHANGELOG.md)
 SHLIB_LINK = $(libpq)
 EXTRA_CLEAN += $(addprefix src/,*.gcno *.gcda) # clean up after profiling runs
 
diff --git a/src/pg_cron.c b/src/pg_cron.c
index e202d14..1c9683a 100644
--- a/src/pg_cron.c
+++ b/src/pg_cron.c
@@ -94,7 +94,11 @@
 #include "utils/builtins.h"
 
 
+#ifdef PG_MODULE_MAGIC_EXT
+PG_MODULE_MAGIC_EXT(.name = "pg_cron", .version = PG_CRON_VERSION);
+#else
 PG_MODULE_MAGIC;
+#endif
 
 #ifndef MAXINT8LEN
 #define MAXINT8LEN 20