diff --git a/src/mime/backend/common.c b/src/mime/backend/common.c
index 33ae01e79..a103c1994 100644
--- a/src/mime/backend/common.c
+++ b/src/mime/backend/common.c
@@ -24,7 +24,7 @@
 #include "mime/backend/mailcap.h"
 #include "mime/backend/mimetypes.h"
 
-static struct mime_backend *mime_backends[] = {
+static const struct mime_backend *const mime_backends[] = {
 	&default_mime_backend,
 #ifdef CONFIG_MAILCAP
 	&mailcap_mime_backend,
@@ -39,7 +39,7 @@ static struct mime_backend *mime_backends[] = {
 unsigned char *
 get_content_type_backends(unsigned char *extension)
 {
-	struct mime_backend *backend;
+	const struct mime_backend *backend;
 	int i;
 
 	foreach_module (backend, mime_backends, i) {
@@ -57,7 +57,7 @@ get_content_type_backends(unsigned char *extension)
 struct mime_handler *
 get_mime_handler_backends(unsigned char *ctype, int have_x)
 {
-	struct mime_backend *backend;
+	const struct mime_backend *backend;
 	int i;
 
 	foreach_module (backend, mime_backends, i) {
diff --git a/src/mime/backend/default.c b/src/mime/backend/default.c
index 3cbc7852c..30f273194 100644
--- a/src/mime/backend/default.c
+++ b/src/mime/backend/default.c
@@ -206,7 +206,7 @@ get_mime_handler_default(unsigned char *type, int have_x)
 }
 
 
-struct mime_backend default_mime_backend = {
+const struct mime_backend default_mime_backend = {
 	/* get_content_type: */	get_content_type_default,
 	/* get_mime_handler: */	get_mime_handler_default,
 };
diff --git a/src/mime/backend/default.h b/src/mime/backend/default.h
index 041f9799a..734531073 100644
--- a/src/mime/backend/default.h
+++ b/src/mime/backend/default.h
@@ -5,7 +5,7 @@
 #include "main/module.h"
 #include "mime/backend/common.h"
 
-extern struct mime_backend default_mime_backend;
+extern const struct mime_backend default_mime_backend;
 extern struct module default_mime_module;
 
 #endif
diff --git a/src/mime/backend/mailcap.c b/src/mime/backend/mailcap.c
index 3bdd2ca19..aaa17b3fb 100644
--- a/src/mime/backend/mailcap.c
+++ b/src/mime/backend/mailcap.c
@@ -661,7 +661,7 @@ get_mime_handler_mailcap(unsigned char *type, int options)
 }
 
 
-struct mime_backend mailcap_mime_backend = {
+const struct mime_backend mailcap_mime_backend = {
 	/* get_content_type: */	NULL,
 	/* get_mime_handler: */	get_mime_handler_mailcap,
 };
diff --git a/src/mime/backend/mailcap.h b/src/mime/backend/mailcap.h
index ce5762498..bf81fd37d 100644
--- a/src/mime/backend/mailcap.h
+++ b/src/mime/backend/mailcap.h
@@ -5,7 +5,7 @@
 #include "main/module.h"
 #include "mime/backend/common.h"
 
-extern struct mime_backend mailcap_mime_backend;
+extern const struct mime_backend mailcap_mime_backend;
 extern struct module mailcap_mime_module;
 
 #endif
diff --git a/src/mime/backend/mimetypes.c b/src/mime/backend/mimetypes.c
index 2b4d8ba62..b9e0b59ca 100644
--- a/src/mime/backend/mimetypes.c
+++ b/src/mime/backend/mimetypes.c
@@ -270,7 +270,7 @@ get_content_type_mimetypes(unsigned char *extension)
 	return NULL;
 }
 
-struct mime_backend mimetypes_mime_backend = {
+const struct mime_backend mimetypes_mime_backend = {
 	/* get_content_type: */	get_content_type_mimetypes,
 	/* get_mime_handler: */	NULL,
 };
diff --git a/src/mime/backend/mimetypes.h b/src/mime/backend/mimetypes.h
index c5b9eebb4..f6a188c5d 100644
--- a/src/mime/backend/mimetypes.h
+++ b/src/mime/backend/mimetypes.h
@@ -5,7 +5,7 @@
 #include "main/module.h"
 #include "mime/backend/common.h"
 
-extern struct mime_backend mimetypes_mime_backend;
+extern const struct mime_backend mimetypes_mime_backend;
 extern struct module mimetypes_mime_module;
 
 #endif