diff --git a/CHANGELOG.md b/CHANGELOG.md
index db5600a..f21625a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,11 @@
+4.2.0
+=====
+
+NEW FEATURES
+------------
+- Add PG_MODULE_MAGIC_EXT() macro for PostgreSQL >= 18.
+- Remove support for PostgreSQL 12.
+
 4.1.0
 =====
 
diff --git a/set_user.control b/set_user.control
index 446d26c..57da330 100644
--- a/set_user.control
+++ b/set_user.control
@@ -1,5 +1,5 @@
 # set_user extension
 comment = 'similar to SET ROLE but with added logging'
-default_version = '4.1.0'
+default_version = '4.2.0'
 module_pathname = '$libdir/set_user'
 relocatable = false
diff --git a/src/compatibility.h b/src/compatibility.h
index e5dcf3b..f9c4446 100644
--- a/src/compatibility.h
+++ b/src/compatibility.h
@@ -16,6 +16,16 @@
 #define NO_ASSERT_AUTH_UID_ONCE !USE_ASSERT_CHECKING
 #endif
 
+/*
+ * Define PG_MODULE_MAGIC_EXT() as PG_MODULE_MAGIC for versions where the new
+ * macro does not exist
+ */
+ #if PG_VERSION_NUM < 180000
+
+ #define PG_MODULE_MAGIC_EXT(...) PG_MODULE_MAGIC
+
+ #endif /* PG_VERSION_NUM < 180000 */
+
 /*
  * PostgreSQL version 17+
  *
diff --git a/src/set_user.c b/src/set_user.c
index 7c91ec9..59062c9 100644
--- a/src/set_user.c
+++ b/src/set_user.c
@@ -53,11 +53,10 @@
 #include "utils/varlena.h"
 
 #include "set_user.h"
-
-PG_MODULE_MAGIC;
-
 #include "compatibility.h"
 
+PG_MODULE_MAGIC_EXT(.name = "set_user", .version = "4.2.0");
+
 #define ALLOWLIST_WILDCARD	"*"
 #define SUPERUSER_AUDIT_TAG	"AUDIT"
 
diff --git a/updates/set_user--4.1.0--4.2.0.sql b/updates/set_user--4.1.0--4.2.0.sql
new file mode 100644
index 0000000..3635207
--- /dev/null
+++ b/updates/set_user--4.1.0--4.2.0.sql
@@ -0,0 +1,2 @@
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION set_user UPDATE" to load this file. \quit