diff --git a/mod_http2/h2.h b/mod_http2/h2.h
index 4127a734..29a31c1a 100644
--- a/mod_http2/h2.h
+++ b/mod_http2/h2.h
@@ -49,7 +49,7 @@ struct h2_stream;
  * The magic PRIamble of RFC 7540 that is always sent when starting
  * a h2 communication.
  */
-extern const char *H2_MAGIC_TOKEN;
+extern const char *const H2_MAGIC_TOKEN;
 
 #define H2_ERR_NO_ERROR             (0x00)
 #define H2_ERR_PROTOCOL_ERROR       (0x01)
diff --git a/mod_http2/h2_protocol.c b/mod_http2/h2_protocol.c
index 874753e4..1d996419 100644
--- a/mod_http2/h2_protocol.c
+++ b/mod_http2/h2_protocol.c
@@ -45,15 +45,15 @@
 #include "h2_protocol.h"
 #include "mod_http2.h"
 
-const char *h2_protocol_ids_tls[] = {
+const char *const h2_protocol_ids_tls[] = {
     "h2", NULL
 };
 
-const char *h2_protocol_ids_clear[] = {
+const char *const h2_protocol_ids_clear[] = {
     "h2c", NULL
 };
 
-const char *H2_MAGIC_TOKEN = "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n";
+const char *const H2_MAGIC_TOKEN = "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n";
 
 /*******************************************************************************
  * HTTP/2 error stuff
diff --git a/mod_http2/h2_protocol.h b/mod_http2/h2_protocol.h
index ed48e896..6b92fab2 100644
--- a/mod_http2/h2_protocol.h
+++ b/mod_http2/h2_protocol.h
@@ -21,13 +21,13 @@
  * List of protocol identifiers that we support in cleartext
  * negotiations. NULL terminated.
  */
-extern const char *h2_protocol_ids_clear[];
+extern const char *const h2_protocol_ids_clear[];
 
 /**
  * List of protocol identifiers that we support in TLS encrypted
  * negotiations (ALPN). NULL terminated.
  */
-extern const char *h2_protocol_ids_tls[];
+extern const char *const h2_protocol_ids_tls[];
 
 /**
  * Provide a user readable description of the HTTP/2 error code-
diff --git a/mod_http2/h2_session.c b/mod_http2/h2_session.c
index 066c73ad..b376080b 100644
--- a/mod_http2/h2_session.c
+++ b/mod_http2/h2_session.c
@@ -1340,7 +1340,7 @@ static void on_stream_output(void *ctx, h2_stream *stream)
 }
 
 
-static const char *StateNames[] = {
+static const char *const StateNames[] = {
     "INIT",      /* H2_SESSION_ST_INIT */
     "DONE",      /* H2_SESSION_ST_DONE */
     "IDLE",      /* H2_SESSION_ST_IDLE */
diff --git a/mod_http2/h2_switch.c b/mod_http2/h2_switch.c
index 37997017..875dd4f2 100644
--- a/mod_http2/h2_switch.c
+++ b/mod_http2/h2_switch.c
@@ -56,7 +56,7 @@ static int h2_protocol_propose(conn_rec *c, request_rec *r,
 {
     int proposed = 0;
     int is_tls = ap_ssl_conn_is_ssl(c);
-    const char **protos = is_tls? h2_protocol_ids_tls : h2_protocol_ids_clear;
+    const char *const *protos = is_tls? h2_protocol_ids_tls : h2_protocol_ids_clear;
     
     if (!h2_mpm_supported()) {
         return DECLINED;
@@ -155,8 +155,8 @@ static int h2_protocol_switch(conn_rec *c, request_rec *r, server_rec *s,
                               const char *protocol)
 {
     int found = 0;
-    const char **protos = ap_ssl_conn_is_ssl(c)? h2_protocol_ids_tls : h2_protocol_ids_clear;
-    const char **p = protos;
+    const char *const *protos = ap_ssl_conn_is_ssl(c)? h2_protocol_ids_tls : h2_protocol_ids_clear;
+    const char *const *p = protos;
     
     (void)s;
     if (!h2_mpm_supported()) {