diff --git a/src/client/opamAdminRepoUpgrade.ml b/src/client/opamAdminRepoUpgrade.ml
index 06eec4a4343..260df43bbac 100644
--- a/src/client/opamAdminRepoUpgrade.ml
+++ b/src/client/opamAdminRepoUpgrade.ml
@@ -217,7 +217,9 @@ let do_upgrade repo_root =
       let descr_file =
         OpamFilename.(opt_file (add_extension (chop_extension comp_file) "descr"))
       in
-      let descr = descr_file >>| fun f -> OpamFile.Descr.read (OpamFile.make f) in
+      let descr =
+        descr_file >>| fun f -> OpamFile.Descr.create (OpamFilename.read f)
+      in
       let nv, ocaml_version, variant =
         match OpamStd.String.cut_at c '+' with
         | None ->
diff --git a/src/format/opamFile.ml b/src/format/opamFile.ml
index 28707cc9658..614e2f703e7 100644
--- a/src/format/opamFile.ml
+++ b/src/format/opamFile.ml
@@ -186,10 +186,7 @@ end
     content. Formerly, (<repo>/packages/.../descr,
     <repo>/compilers/.../<v>.descr) *)
 
-module DescrIO = struct
-
-  let internal = "descr"
-  let format_version = OpamVersion.of_string "0"
+module Descr = struct
 
   type t = string * string
 
@@ -203,24 +200,6 @@ module DescrIO = struct
     | "" -> x ^ "\n"
     | y -> String.concat "" [x; "\n\n"; y; "\n"]
 
-  let of_channel _ ic =
-    let x =
-      try OpamStd.String.strip (input_line ic)
-      with End_of_file | Sys_error _ -> "" in
-    let y =
-      try OpamStd.String.strip (OpamSystem.string_of_channel ic)
-      with End_of_file | Sys_error _ -> ""
-    in
-    x, y
-
-  let to_channel _ oc (x,y) =
-    output_string oc x;
-    output_char oc '\n';
-    if y <> "" then
-      (output_char oc '\n';
-       output_string oc y;
-       output_char oc '\n')
-
   let create str =
     let head, tail =
       match OpamStd.String.cut_at str '\n' with
@@ -228,14 +207,6 @@ module DescrIO = struct
       | Some (h,t) -> h, t in
     OpamStd.String.strip head, OpamStd.String.strip tail
 
-  let of_string _ = create
-
-  let to_string _ = full
-
-end
-module Descr = struct
-  include DescrIO
-  include MakeIO(DescrIO)
 end
 
 (* module Comp_descr = Descr *)
@@ -3182,7 +3153,7 @@ module OPAMSyntax = struct
         Pp.V.os_constraint;
       "descr", no_cleanup Pp.ppacc_opt with_descr OpamStd.Option.none
         (Pp.V.string_tr -|
-         Pp.of_pair "descr" Descr.(of_string (), to_string ()));
+         Pp.of_pair "descr" Descr.(create, full));
       "extra-sources", no_cleanup Pp.ppacc_opt
         with_extra_sources OpamStd.Option.none
         (Pp.V.map_list ~depth:2 @@
diff --git a/src/format/opamFile.mli b/src/format/opamFile.mli
index 00d529c84a8..abd8b4e2d91 100644
--- a/src/format/opamFile.mli
+++ b/src/format/opamFile.mli
@@ -298,12 +298,11 @@ end
 (** Package descriptions: [$opam/descr/] *)
 module Descr: sig
 
-  include IO_FILE
+  type t
 
-  val create: string -> t
+  val empty : t
 
-  (** Create an abstract description file from a string *)
-  val of_string: t typed_file -> string -> t
+  val create: string -> t
 
   (** Return the first line *)
   val synopsis: t -> string
diff --git a/src/state/opamFormatUpgrade.ml b/src/state/opamFormatUpgrade.ml
index d2304e5c4f6..71e08042bb9 100644
--- a/src/state/opamFormatUpgrade.ml
+++ b/src/state/opamFormatUpgrade.ml
@@ -563,7 +563,11 @@ let from_1_3_dev2_to_1_3_dev5 ~on_the_fly:_ root conf =
             OpamStd.Option.default
               (OpamFile.Descr.create
                  "Switch relying on a system-wide installation of OCaml")
-              (OpamFile.Descr.read_opt descr_f)
+              (if OpamFile.exists descr_f then
+                 Some (OpamFile.Descr.create
+                         (OpamSystem.read (OpamFile.to_string descr_f)))
+               else
+                 None)
           in
           let comp_opam =
             OpamFile.Comp.to_package comp (Some descr)