diff --git a/Documentation/Reference/Module-Commands.md b/Documentation/Reference/Module-Commands.md
index b4377b9bf..251024fca 100644
--- a/Documentation/Reference/Module-Commands.md
+++ b/Documentation/Reference/Module-Commands.md
@@ -19,7 +19,7 @@ The following example registers the module command _my_command_ for module
 _my_module_.
 
 ```
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 
 bool my_simple_cmd(const MODULECMD_ARG *argv)
 {
diff --git a/examples/roundrobinrouter.cpp b/examples/roundrobinrouter.cpp
index 039b81971..8f062ef80 100644
--- a/examples/roundrobinrouter.cpp
+++ b/examples/roundrobinrouter.cpp
@@ -43,7 +43,7 @@
 #include <maxscale/buffer.h>
 #include <maxscale/dcb.h>
 #include <maxscale/modinfo.h>
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 #include <maxscale/modutil.h>
 #include <maxscale/protocol/mysql.h>
 #include <maxscale/query_classifier.h>
diff --git a/include/maxscale/modulecmd.h b/include/maxscale/modulecmd.hh
similarity index 98%
rename from include/maxscale/modulecmd.h
rename to include/maxscale/modulecmd.hh
index fba303235..a8a933a83 100644
--- a/include/maxscale/modulecmd.h
+++ b/include/maxscale/modulecmd.hh
@@ -13,7 +13,7 @@
 #pragma once
 
 /**
- * @file module_command.h Module driven commands
+ * @file module_command.hh Module driven commands
  *
  * This header describes the structures and functions used to register new
  * functions for modules. It allows modules to introduce custom commands that
@@ -22,14 +22,14 @@
  * same functionality again.
  */
 
-#include <maxscale/cdefs.h>
+#include <maxscale/ccdefs.hh>
 #include <maxbase/jansson.h>
 #include <maxscale/dcb.h>
-#include <maxscale/filter.h>
-#include <maxscale/monitor.h>
-#include <maxscale/server.h>
+#include <maxscale/filter.hh>
+#include <maxscale/monitor.hh>
+#include <maxscale/server.hh>
 #include <maxscale/service.hh>
-#include <maxscale/session.h>
+#include <maxscale/session.hh>
 
 MXS_BEGIN_DECLS
 
diff --git a/server/core/load_utils.cc b/server/core/load_utils.cc
index db026eb2c..287c5bbe6 100644
--- a/server/core/load_utils.cc
+++ b/server/core/load_utils.cc
@@ -30,7 +30,7 @@
 #include <maxscale/paths.h>
 #include <maxscale/alloc.h>
 #include <maxscale/json_api.h>
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 #include <maxscale/protocol.h>
 #include <maxscale/router.h>
 #include <maxscale/filter.h>
diff --git a/server/core/modulecmd.cc b/server/core/modulecmd.cc
index 5b13dac46..60e0a64b5 100644
--- a/server/core/modulecmd.cc
+++ b/server/core/modulecmd.cc
@@ -11,7 +11,7 @@
  * Public License.
  */
 
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 
 #include <string>
 
diff --git a/server/core/resource.cc b/server/core/resource.cc
index 46ab9ef0c..e90b72d4f 100644
--- a/server/core/resource.cc
+++ b/server/core/resource.cc
@@ -22,7 +22,7 @@
 #include <maxscale/http.hh>
 #include <maxscale/jansson.hh>
 #include <maxscale/json_api.h>
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 #include <maxscale/server.hh>
 #include <maxscale/routingworker.hh>
 
diff --git a/server/core/test/test_modulecmd.cc b/server/core/test/test_modulecmd.cc
index 459c61186..b7c0133c0 100644
--- a/server/core/test/test_modulecmd.cc
+++ b/server/core/test/test_modulecmd.cc
@@ -19,7 +19,7 @@
 #include <maxscale/alloc.h>
 #include <maxscale/dcb.h>
 #include <maxscale/paths.h>
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 #include <maxscale/session.h>
 #include <maxscale/json_api.h>
 
diff --git a/server/modules/authenticator/CDCPlainAuth/cdc_plain_auth.cc b/server/modules/authenticator/CDCPlainAuth/cdc_plain_auth.cc
index 9ac822fc9..37366be18 100644
--- a/server/modules/authenticator/CDCPlainAuth/cdc_plain_auth.cc
+++ b/server/modules/authenticator/CDCPlainAuth/cdc_plain_auth.cc
@@ -33,7 +33,7 @@
 #include <cdc.h>
 #include <maxscale/alloc.h>
 #include <maxscale/event.hh>
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 #include <maxscale/modutil.h>
 #include <maxscale/paths.h>
 #include <maxscale/secrets.h>
diff --git a/server/modules/filter/cache/cachefilter.cc b/server/modules/filter/cache/cachefilter.cc
index ed6b31e4d..2ff9f237d 100644
--- a/server/modules/filter/cache/cachefilter.cc
+++ b/server/modules/filter/cache/cachefilter.cc
@@ -16,7 +16,7 @@
 
 #include <maxscale/alloc.h>
 #include <maxscale/jansson.hh>
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 #include <maxscale/paths.h>
 #include <maxscale/utils.h>
 
diff --git a/server/modules/filter/dbfwfilter/dbfwfilter.cc b/server/modules/filter/dbfwfilter/dbfwfilter.cc
index 84bbc597f..d766a0955 100644
--- a/server/modules/filter/dbfwfilter/dbfwfilter.cc
+++ b/server/modules/filter/dbfwfilter/dbfwfilter.cc
@@ -70,7 +70,7 @@
 #include <map>
 
 #include <maxbase/atomic.h>
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 #include <maxscale/modutil.h>
 #include <maxscale/log.h>
 #include <maxscale/protocol/mysql.h>
diff --git a/server/modules/filter/masking/maskingfilter.cc b/server/modules/filter/masking/maskingfilter.cc
index 59b7a6dc3..0db2e1ad8 100644
--- a/server/modules/filter/masking/maskingfilter.cc
+++ b/server/modules/filter/masking/maskingfilter.cc
@@ -15,7 +15,7 @@
 #include "maskingfilter.hh"
 
 #include <maxscale/json_api.h>
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 #include <maxscale/paths.h>
 #include <maxscale/utils.h>
 
diff --git a/server/modules/filter/qlafilter/qlafilter.cc b/server/modules/filter/qlafilter/qlafilter.cc
index 35d7b9df5..158c81eb6 100644
--- a/server/modules/filter/qlafilter/qlafilter.cc
+++ b/server/modules/filter/qlafilter/qlafilter.cc
@@ -46,7 +46,7 @@
 #include <maxscale/pcre2.h>
 #include <maxscale/service.hh>
 #include <maxscale/utils.h>
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 #include <maxscale/json_api.h>
 
 using std::string;
diff --git a/server/modules/filter/tee/tee.cc b/server/modules/filter/tee/tee.cc
index 218ad4233..b07662eb2 100644
--- a/server/modules/filter/tee/tee.cc
+++ b/server/modules/filter/tee/tee.cc
@@ -22,7 +22,7 @@
 #include <maxscale/alloc.h>
 #include <maxscale/modinfo.h>
 #include <maxscale/log.h>
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 
 #include "tee.hh"
 #include "teesession.hh"
diff --git a/server/modules/monitor/mariadbmon/mariadbmon.cc b/server/modules/monitor/mariadbmon/mariadbmon.cc
index 67a47fd45..c125164ea 100644
--- a/server/modules/monitor/mariadbmon/mariadbmon.cc
+++ b/server/modules/monitor/mariadbmon/mariadbmon.cc
@@ -22,7 +22,7 @@
 #include <maxbase/format.hh>
 #include <maxscale/alloc.h>
 #include <maxscale/dcb.h>
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 #include <maxscale/mysql_utils.hh>
 #include <maxscale/routingworker.h>
 #include <maxscale/secrets.h>
diff --git a/server/modules/routing/avrorouter/avro.cc b/server/modules/routing/avrorouter/avro.cc
index 0942a6c5f..8fd8e9223 100644
--- a/server/modules/routing/avrorouter/avro.cc
+++ b/server/modules/routing/avrorouter/avro.cc
@@ -33,7 +33,7 @@
 #include <maxscale/alloc.h>
 #include <maxscale/dcb.h>
 #include <maxscale/log.h>
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 #include <maxscale/paths.h>
 #include <maxscale/protocol/mysql.h>
 #include <maxscale/random.h>
diff --git a/server/modules/routing/avrorouter/avro_main.cc b/server/modules/routing/avrorouter/avro_main.cc
index ac93223ff..df212ee86 100644
--- a/server/modules/routing/avrorouter/avro_main.cc
+++ b/server/modules/routing/avrorouter/avro_main.cc
@@ -29,7 +29,7 @@
 #include <maxscale/alloc.h>
 #include <maxscale/dcb.h>
 #include <maxscale/log.h>
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 #include <maxscale/paths.h>
 #include <maxscale/protocol/mysql.h>
 #include <maxscale/random.h>
diff --git a/server/modules/routing/debugcli/debugcmd.cc b/server/modules/routing/debugcli/debugcmd.cc
index cd37c1063..8ccf95b54 100644
--- a/server/modules/routing/debugcli/debugcmd.cc
+++ b/server/modules/routing/debugcli/debugcmd.cc
@@ -45,7 +45,7 @@
 #include <maxscale/housekeeper.h>
 #include <maxscale/log.h>
 #include <maxscale/maxscale.h>
-#include <maxscale/modulecmd.h>
+#include <maxscale/modulecmd.hh>
 #include <maxscale/router.h>
 #include <maxscale/routingworker.hh>
 #include <maxscale/server.hh>