diff --git a/common/message/client_info.hpp b/common/message/client_info.hpp
index cf918939..06331841 100644
--- a/common/message/client_info.hpp
+++ b/common/message/client_info.hpp
@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2020  Johannes Pohl
+    Copyright (C) 2014-2022  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -16,9 +16,10 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#ifndef CLIENT_INFO_H
-#define CLIENT_INFO_H
+#ifndef MESSAGE_CLIENT_INFO_HPP
+#define MESSAGE_CLIENT_INFO_HPP
 
+// local headers
 #include "json_message.hpp"
 
 
diff --git a/common/message/codec_header.hpp b/common/message/codec_header.hpp
index 132cb13f..cf34eb5e 100644
--- a/common/message/codec_header.hpp
+++ b/common/message/codec_header.hpp
@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2020  Johannes Pohl
+    Copyright (C) 2014-2022  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -16,9 +16,10 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#ifndef CODEC_HEADER_MESSAGE_H
-#define CODEC_HEADER_MESSAGE_H
+#ifndef MESSAGE_CODEC_HEADER_HPP
+#define MESSAGE_CODEC_HEADER_HPP
 
+// local headers
 #include "message.hpp"
 
 namespace msg
diff --git a/common/message/factory.hpp b/common/message/factory.hpp
index c166edf0..e0014393 100644
--- a/common/message/factory.hpp
+++ b/common/message/factory.hpp
@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2021  Johannes Pohl
+    Copyright (C) 2014-2022  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -19,17 +19,18 @@
 #ifndef MESSAGE_FACTORY_HPP
 #define MESSAGE_FACTORY_HPP
 
+// local headers
 #include "client_info.hpp"
 #include "codec_header.hpp"
-#include "hello.hpp"
-#include "pcm_chunk.hpp"
-#include "server_settings.hpp"
-// #include "stream_tags.hpp"
-#include "time.hpp"
-
 #include "common/str_compat.hpp"
 #include "common/utils.hpp"
+#include "hello.hpp"
 #include "json_message.hpp"
+#include "pcm_chunk.hpp"
+#include "server_settings.hpp"
+#include "time.hpp"
+
+// standard headers
 #include <string>
 
 
diff --git a/common/message/hello.hpp b/common/message/hello.hpp
index d2cdfb63..3deb161e 100644
--- a/common/message/hello.hpp
+++ b/common/message/hello.hpp
@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2020  Johannes Pohl
+    Copyright (C) 2014-2022  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -16,12 +16,15 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#ifndef HELLO_MSG_H
-#define HELLO_MSG_H
+#ifndef MESSAGE_HELLO_HPP
+#define MESSAGE_HELLO_HPP
 
+// local headers
 #include "common/str_compat.hpp"
 #include "common/utils.hpp"
 #include "json_message.hpp"
+
+// standard headers
 #include <string>
 
 
diff --git a/common/message/json_message.hpp b/common/message/json_message.hpp
index ffd29551..127a1d33 100644
--- a/common/message/json_message.hpp
+++ b/common/message/json_message.hpp
@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2020  Johannes Pohl
+    Copyright (C) 2014-2022  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -16,9 +16,10 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#ifndef JSON_MESSAGE_H
-#define JSON_MESSAGE_H
+#ifndef MESSAGE_JSON_HPP
+#define MESSAGE_JSON_HPP
 
+// local headers
 #include "common/json.hpp"
 #include "message.hpp"
 
diff --git a/common/message/message.hpp b/common/message/message.hpp
index 6fddbe7d..820faa93 100644
--- a/common/message/message.hpp
+++ b/common/message/message.hpp
@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2021  Johannes Pohl
+    Copyright (C) 2014-2022  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -16,11 +16,14 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#ifndef MESSAGE_HPP
-#define MESSAGE_HPP
+#ifndef MESSAGE_MESSAGE_HPP
+#define MESSAGE_MESSAGE_HPP
 
+// local headers
 #include "common/endian.hpp"
 #include "common/time_defs.hpp"
+
+// standard headers
 #include <cstdlib>
 #include <cstring>
 #include <iostream>
diff --git a/common/message/pcm_chunk.hpp b/common/message/pcm_chunk.hpp
index c3a9b954..16ae3969 100644
--- a/common/message/pcm_chunk.hpp
+++ b/common/message/pcm_chunk.hpp
@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2020  Johannes Pohl
+    Copyright (C) 2014-2022  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -16,12 +16,15 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#ifndef PCM_CHUNK_H
-#define PCM_CHUNK_H
+#ifndef MESSAGE_PCM_CHUNK_HPP
+#define MESSAGE_PCM_CHUNK_HPP
 
+// local headers
 #include "common/sample_format.hpp"
 #include "message.hpp"
 #include "wire_chunk.hpp"
+
+// standard headers
 #include <chrono>
 
 
diff --git a/common/message/server_settings.hpp b/common/message/server_settings.hpp
index a5b86fe8..0979118a 100644
--- a/common/message/server_settings.hpp
+++ b/common/message/server_settings.hpp
@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2020  Johannes Pohl
+    Copyright (C) 2014-2022  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -16,9 +16,10 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#ifndef SERVER_SETTINGS_H
-#define SERVER_SETTINGS_H
+#ifndef MESSAGE_SERVER_SETTINGS_HPP
+#define MESSAGE_SERVER_SETTINGS_HPP
 
+// local headers
 #include "json_message.hpp"
 
 
diff --git a/common/message/stream_tags.hpp b/common/message/stream_tags.hpp
index b74c3ade..2f0a736d 100644
--- a/common/message/stream_tags.hpp
+++ b/common/message/stream_tags.hpp
@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2021  Johannes Pohl
+    Copyright (C) 2014-2022  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -16,10 +16,10 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#ifndef STREAMTAGS_HPP
-#define STREAMTAGS_HPP
+#ifndef MESSAGE_STREAM_TAGS_HPP
+#define MESSAGE_STREAM_TAGS_HPP
 
-// #include "common/metatags.hpp"
+// local headers
 #include "json_message.hpp"
 
 /*
diff --git a/common/message/time.hpp b/common/message/time.hpp
index 195d0ac5..3abc18bb 100644
--- a/common/message/time.hpp
+++ b/common/message/time.hpp
@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2020  Johannes Pohl
+    Copyright (C) 2014-2022  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -16,9 +16,10 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#ifndef TIME_MSG_H
-#define TIME_MSG_H
+#ifndef MESSAGE_TIME_HPP
+#define MESSAGE_TIME_HPP
 
+// local headers
 #include "message.hpp"
 
 namespace msg
diff --git a/common/message/wire_chunk.hpp b/common/message/wire_chunk.hpp
index 75f00ef6..a11a2623 100644
--- a/common/message/wire_chunk.hpp
+++ b/common/message/wire_chunk.hpp
@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2020  Johannes Pohl
+    Copyright (C) 2014-2022  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -16,11 +16,14 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#ifndef WIRE_CHUNK_H
-#define WIRE_CHUNK_H
+#ifndef MESSAGE_WIRE_CHUNK_HPP
+#define MESSAGE_WIRE_CHUNK_HPP
 
+// local headers
 #include "common/time_defs.hpp"
 #include "message.hpp"
+
+// standard headers
 #include <chrono>
 #include <cstdlib>
 #include <cstring>