diff --git a/LICENSE b/LICENSE
index 3106cd6..6162359 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright (c) 2015-2022, Michael Santos <michael.santos@gmail.com>
+Copyright (c) 2015-2023, Michael Santos <michael.santos@gmail.com>
 
 Permission to use, copy, modify, and/or distribute this software for any
 purpose with or without fee is hereby granted, provided that the above
diff --git a/src/xmppipe_fmt.c b/src/xmppipe_fmt.c
index 3974b88..4b4bf4a 100644
--- a/src/xmppipe_fmt.c
+++ b/src/xmppipe_fmt.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2015-2016, Michael Santos <michael.santos@gmail.com>
+/* Copyright (c) 2015-2023, Michael Santos <michael.santos@gmail.com>
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -17,7 +17,7 @@
 
 static unsigned char rfc3986[256];
 
-int xmppipe_fmt_init() {
+int xmppipe_fmt_init(void) {
   int i = 0;
 
   for (i = 0; i < 256; i++)
diff --git a/src/xmppipe_util.c b/src/xmppipe_util.c
index ca23877..ad26fc3 100644
--- a/src/xmppipe_util.c
+++ b/src/xmppipe_util.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2015-2022, Michael Santos <michael.santos@gmail.com>
+/* Copyright (c) 2015-2023, Michael Santos <michael.santos@gmail.com>
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -218,7 +218,7 @@ char *xmppipe_servername(char *jid) {
   return q;
 }
 
-char *xmppipe_resource() {
+char *xmppipe_resource(void) {
   char buf[11];
 
   (void)snprintf(buf, sizeof(buf), "%d", getpid());