diff --git a/include/corosync/cpg.h b/include/corosync/cpg.h
index 30e4b791..644d8d8d 100644
--- a/include/corosync/cpg.h
+++ b/include/corosync/cpg.h
@@ -88,7 +88,7 @@ typedef void (*cpg_deliver_fn_t) (
 	const struct cpg_name *group_name,
 	uint32_t nodeid,
 	uint32_t pid,
-	const void *msg,
+	void *msg,
 	size_t msg_len);
 
 typedef void (*cpg_confchg_fn_t) (
diff --git a/test/cpgbench.c b/test/cpgbench.c
index aff3acf2..7663103e 100644
--- a/test/cpgbench.c
+++ b/test/cpgbench.c
@@ -85,7 +85,7 @@ static void cpg_bm_deliver_fn (
         const struct cpg_name *group_name,
         uint32_t nodeid,
         uint32_t pid,
-        const void *msg,
+        void *msg,
         size_t msg_len)
 {
 	write_count++;
diff --git a/test/cpgbenchzc.c b/test/cpgbenchzc.c
index 2f8c0fb8..360c5331 100644
--- a/test/cpgbenchzc.c
+++ b/test/cpgbenchzc.c
@@ -85,7 +85,7 @@ static void cpg_bm_deliver_fn (
         const struct cpg_name *group_name,
         uint32_t nodeid,
         uint32_t pid,
-        const void *msg,
+        void *msg,
         size_t msg_len)
 {
 	write_count++;
diff --git a/test/testcpg.c b/test/testcpg.c
index b4d5d9f4..465933a3 100644
--- a/test/testcpg.c
+++ b/test/testcpg.c
@@ -67,7 +67,7 @@ static void DeliverCallback (
 	const struct cpg_name *groupName,
 	uint32_t nodeid,
 	uint32_t pid,
-	const void *msg,
+	void *msg,
 	size_t msg_len)
 {
 	if (show_ip) {
diff --git a/test/testcpg2.c b/test/testcpg2.c
index f0218c42..ff53edd9 100644
--- a/test/testcpg2.c
+++ b/test/testcpg2.c
@@ -48,7 +48,7 @@ static void deliver(
 	const struct cpg_name *group_name,
 	uint32_t nodeid,
 	uint32_t pid,
-	const void *msg,
+	void *msg,
 	size_t msg_len)
 {
     printf("self delivered nodeid: %x\n", nodeid);
diff --git a/test/testcpgzc.c b/test/testcpgzc.c
index 9e139667..6c7e3760 100644
--- a/test/testcpgzc.c
+++ b/test/testcpgzc.c
@@ -67,7 +67,7 @@ static void DeliverCallback (
 	const struct cpg_name *groupName,
 	uint32_t nodeid,
 	uint32_t pid,
-	const void *msg,
+	void *msg,
 	size_t msg_len)
 {
 	if (show_ip) {
diff --git a/test/testzcgc.c b/test/testzcgc.c
index da376554..7ec8a0ed 100644
--- a/test/testzcgc.c
+++ b/test/testzcgc.c
@@ -67,7 +67,7 @@ static void DeliverCallback (
 	const struct cpg_name *groupName,
 	uint32_t nodeid,
 	uint32_t pid,
-	const void *msg,
+	void *msg,
 	size_t msg_len)
 {
 	if (show_ip) {