diff --git a/src/libcrun/container.c b/src/libcrun/container.c
index 37e59312b..401b75ed6 100644
--- a/src/libcrun/container.c
+++ b/src/libcrun/container.c
@@ -3886,7 +3886,7 @@ libcrun_container_get_features (libcrun_context_t *context, struct features_info
 
   // Hardcoded feature information
   (*info)->oci_version_min = xstrdup ("1.0.0");
-  (*info)->oci_version_max = xstrdup ("1.1.0");
+  (*info)->oci_version_max = xstrdup ("1.1.0+dev");
 
   // Populate hooks
   populate_array_field (&((*info)->hooks), hooks, num_hooks);
@@ -3925,6 +3925,9 @@ libcrun_container_get_features (libcrun_context_t *context, struct features_info
   (*info)->linux.apparmor.enabled = true;
   (*info)->linux.selinux.enabled = true;
 
+  // Put the values for mount extensions
+  (*info)->linux.mount_ext.idmap.enabled = true;
+
   // Populate the values for annotations
 #ifdef HAVE_SECCOMP
   {
diff --git a/src/libcrun/container.h b/src/libcrun/container.h
index 2511d0a0f..8d87052a1 100644
--- a/src/libcrun/container.h
+++ b/src/libcrun/container.h
@@ -121,6 +121,16 @@ struct selinux_info_s
   bool enabled;
 };
 
+struct idmap_info_s
+{
+  bool enabled;
+};
+
+struct mount_ext_info_s
+{
+  struct idmap_info_s idmap;
+};
+
 struct linux_info_s
 {
   char **namespaces;
@@ -129,6 +139,7 @@ struct linux_info_s
   struct seccomp_info_s seccomp;
   struct apparmor_info_s apparmor;
   struct selinux_info_s selinux;
+  struct mount_ext_info_s mount_ext;
 };
 
 struct annotations_info_s
diff --git a/src/oci_features.c b/src/oci_features.c
index f62c10884..b13449b42 100644
--- a/src/oci_features.c
+++ b/src/oci_features.c
@@ -170,6 +170,20 @@ crun_features_add_selinux_info (yajl_gen json_gen, const struct linux_info_s *li
   yajl_gen_map_close (json_gen);
 }
 
+void
+crun_features_add_mount_ext_info (yajl_gen json_gen, const struct linux_info_s *linux)
+{
+  yajl_gen_string (json_gen, (const unsigned char *) "mountExtensions", strlen ("mountExtensions"));
+  yajl_gen_map_open (json_gen);
+
+  yajl_gen_string (json_gen, (const unsigned char *) "idmap", strlen ("idmap"));
+  yajl_gen_map_open (json_gen);
+  add_bool_to_json (json_gen, "enabled", linux->mount_ext.idmap.enabled);
+  yajl_gen_map_close (json_gen);
+
+  yajl_gen_map_close (json_gen);
+}
+
 void
 crun_features_add_linux_info (yajl_gen json_gen, const struct linux_info_s *linux)
 {
@@ -182,6 +196,7 @@ crun_features_add_linux_info (yajl_gen json_gen, const struct linux_info_s *linu
   crun_features_add_seccomp_info (json_gen, linux);
   crun_features_add_apparmor_info (json_gen, linux);
   crun_features_add_selinux_info (json_gen, linux);
+  crun_features_add_mount_ext_info (json_gen, linux);
 
   yajl_gen_map_close (json_gen);
 }
diff --git a/tests/test_oci_features.py b/tests/test_oci_features.py
index 3188175c5..59ca7b489 100644
--- a/tests/test_oci_features.py
+++ b/tests/test_oci_features.py
@@ -45,7 +45,7 @@ def test_crun_features():
         features = json.loads(output)
         expected_features = {
             "ociVersionMin": "1.0.0",
-            "ociVersionMax": "1.1.0",
+            "ociVersionMax": "1.1.0+dev",
             "hooks": [
                 "prestart",
                 "createRuntime",
@@ -155,6 +155,11 @@ def test_crun_features():
                 },
                 "selinux": {
                     "enabled": True
+                },
+                "mountExtensions": {
+                    "idmap": {
+                        "enabled": True,
+                    },
                 }
             },
             "annotations": {