diff --git a/ocaml/tests/test_sm_features.ml b/ocaml/tests/test_sm_features.ml
index 3aff2f31723..506d467b56f 100644
--- a/ocaml/tests/test_sm_features.ml
+++ b/ocaml/tests/test_sm_features.ml
@@ -47,55 +47,53 @@ let test_sequences =
     {
       raw=
         [
-          "SR_PROBE"
-        ; "SR_UPDATE"
+          "ATOMIC_PAUSE"
         ; "SR_CACHING"
-        ; (* xapi ignores this. *)
-          "VDI_CREATE"
-        ; "VDI_DELETE"
+        ; "SR_PROBE"
+        ; "SR_UPDATE"
         ; "VDI_ATTACH"
-        ; "VDI_DETACH"
-        ; "VDI_UPDATE"
         ; "VDI_CLONE"
-        ; "VDI_SNAPSHOT"
-        ; "VDI_RESIZE"
+        ; "VDI_CONFIG_CBT"
+        ; "VDI_CREATE"
+        ; "VDI_DELETE"
+        ; "VDI_DETACH"
         ; "VDI_GENERATE_CONFIG"
         ; "VDI_RESET_ON_BOOT/2"
-        ; "VDI_CONFIG_CBT"
-        ; "ATOMIC_PAUSE"
-          (* xapi ignores this *)
+        ; "VDI_RESIZE"
+        ; "VDI_SNAPSHOT"
+        ; "VDI_UPDATE"
         ]
     ; smapiv1_features=
         [
           (Sr_probe, 1L)
         ; (Sr_update, 1L)
+        ; (Vdi_attach, 1L)
+        ; (Vdi_clone, 1L)
+        ; (Vdi_configure_cbt, 1L)
         ; (Vdi_create, 1L)
         ; (Vdi_delete, 1L)
-        ; (Vdi_attach, 1L)
         ; (Vdi_detach, 1L)
-        ; (Vdi_update, 1L)
-        ; (Vdi_clone, 1L)
-        ; (Vdi_snapshot, 1L)
-        ; (Vdi_resize, 1L)
         ; (Vdi_generate_config, 1L)
         ; (Vdi_reset_on_boot, 2L)
-        ; (Vdi_configure_cbt, 1L)
+        ; (Vdi_resize, 1L)
+        ; (Vdi_snapshot, 1L)
+        ; (Vdi_update, 1L)
         ]
     ; smapiv2_features=
         [
           "SR_PROBE/1"
         ; "SR_UPDATE/1"
+        ; "VDI_ATTACH/1"
+        ; "VDI_CLONE/1"
+        ; "VDI_CONFIG_CBT/1"
         ; "VDI_CREATE/1"
         ; "VDI_DELETE/1"
-        ; "VDI_ATTACH/1"
         ; "VDI_DETACH/1"
-        ; "VDI_UPDATE/1"
-        ; "VDI_CLONE/1"
-        ; "VDI_SNAPSHOT/1"
-        ; "VDI_RESIZE/1"
         ; "VDI_GENERATE_CONFIG/1"
         ; "VDI_RESET_ON_BOOT/2"
-        ; "VDI_CONFIG_CBT/1"
+        ; "VDI_RESIZE/1"
+        ; "VDI_SNAPSHOT/1"
+        ; "VDI_UPDATE/1"
         ]
     ; sm=
         {
@@ -103,33 +101,33 @@ let test_sequences =
             [
               "SR_PROBE"
             ; "SR_UPDATE"
+            ; "VDI_ATTACH"
+            ; "VDI_CLONE"
+            ; "VDI_CONFIG_CBT"
             ; "VDI_CREATE"
             ; "VDI_DELETE"
-            ; "VDI_ATTACH"
             ; "VDI_DETACH"
-            ; "VDI_UPDATE"
-            ; "VDI_CLONE"
-            ; "VDI_SNAPSHOT"
-            ; "VDI_RESIZE"
             ; "VDI_GENERATE_CONFIG"
             ; "VDI_RESET_ON_BOOT"
-            ; "VDI_CONFIG_CBT"
+            ; "VDI_RESIZE"
+            ; "VDI_SNAPSHOT"
+            ; "VDI_UPDATE"
             ]
         ; features=
             [
               ("SR_PROBE", 1L)
             ; ("SR_UPDATE", 1L)
+            ; ("VDI_ATTACH", 1L)
+            ; ("VDI_CLONE", 1L)
+            ; ("VDI_CONFIG_CBT", 1L)
             ; ("VDI_CREATE", 1L)
             ; ("VDI_DELETE", 1L)
-            ; ("VDI_ATTACH", 1L)
             ; ("VDI_DETACH", 1L)
-            ; ("VDI_UPDATE", 1L)
-            ; ("VDI_CLONE", 1L)
-            ; ("VDI_SNAPSHOT", 1L)
-            ; ("VDI_RESIZE", 1L)
             ; ("VDI_GENERATE_CONFIG", 1L)
             ; ("VDI_RESET_ON_BOOT", 2L)
-            ; ("VDI_CONFIG_CBT", 1L)
+            ; ("VDI_RESIZE", 1L)
+            ; ("VDI_SNAPSHOT", 1L)
+            ; ("VDI_UPDATE", 1L)
             ]
         }
     }
diff --git a/ocaml/xapi/smint.ml b/ocaml/xapi/smint.ml
index 69cb55231e3..ddec92f2c3b 100644
--- a/ocaml/xapi/smint.ml
+++ b/ocaml/xapi/smint.ml
@@ -106,34 +106,31 @@ let has_capability (c : capability) fl = List.mem_assoc c fl
 
 let capability_of_feature : feature -> capability = fst
 
-let parse_string_int64_features strings =
-  let text_features =
-    List.filter
-      (fun s ->
-        let s = List.hd (Stdext.Xstringext.String.split '/' s) in
-        let p = List.mem s (List.map fst string_to_capability_table) in
-        if not p then debug "SM.feature: unknown feature %s" s ;
-        p
-      )
-      strings
-  in
-  List.map
-    (fun c ->
-      match Stdext.Xstringext.String.split '/' c with
-      | [] ->
-          failwith "parse_feature" (* not possible *)
-      | [cs] ->
-          (cs, 1L) (* default version *)
-      | [cs; vs] | cs :: vs :: _ -> (
-        try
-          let v = int_of_string vs in
-          (cs, if v < 1 then 1L else Int64.of_int v)
-        with _ ->
-          debug "SM.feature %s has bad version %s, defaulting to 1" cs vs ;
-          (cs, 1L)
-      )
+let known_features = List.map fst string_to_capability_table
+
+let parse_string_int64_features features =
+  let scan feature =
+    match String.split_on_char '/' feature with
+    | [] ->
+        None
+    | [feature] when List.mem feature known_features ->
+        Some (feature, 1L)
+    | feature :: version :: _ when List.mem feature known_features -> (
+      try
+        let v = Int64.(max 1L (of_string version)) in
+        Some (feature, v)
+      with _ ->
+        debug "SM.feature: %s has bad version %s, defaulting to 1" feature
+          version ;
+        Some (feature, 1L)
     )
-    text_features
+    | feature :: _ ->
+        error "SM.feature: unknown feature %s" feature ;
+        None
+  in
+  features
+  |> List.filter_map scan
+  |> List.sort_uniq (fun (x, _) (y, _) -> compare x y)
 
 let parse_capability_int64_features strings =
   List.map