diff --git a/plotkicadsch.opam b/plotkicadsch.opam
index 41920ea..1f0c25a 100644
--- a/plotkicadsch.opam
+++ b/plotkicadsch.opam
@@ -26,7 +26,7 @@ depends: [
   "sha"
   "git" {>= "2.0.0"}
   "git-unix"
-  "base64" {= "2.3.0"}
+  "base64" {>= "3.0.0"}
   "patience_diff" { < "v0.12.0" }
   "core_kernel"
   "cmdliner"
diff --git a/plotkicadsch/src/kicadDiff.ml b/plotkicadsch/src/kicadDiff.ml
index d8653eb..2b0b3ab 100644
--- a/plotkicadsch/src/kicadDiff.ml
+++ b/plotkicadsch/src/kicadDiff.ml
@@ -81,7 +81,7 @@ let intersect_lists l1l l2l =
     ~f:(fun (name2, sha2) ->
         List.exists
           ~f:(fun (name1, sha1) ->
-              List.equal ~equal:String.equal name1 name2 && not (String.equal sha2 sha1) )
+              List.equal String.equal name1 name2 && not (String.equal sha2 sha1) )
           l1 )
     l2
   |> List.map ~f:fst
diff --git a/plotkicadsch/src/svgPainter.ml b/plotkicadsch/src/svgPainter.ml
index 87ffcd7..8c5fdb0 100644
--- a/plotkicadsch/src/svgPainter.ml
+++ b/plotkicadsch/src/svgPainter.ml
@@ -175,7 +175,8 @@ exception Base64Exception of string
 let paint_image (Coord (x, y)) scale b ({c; _} as ctxt) =
   let s = scale /. 0.3 in
   let w, h = get_png_dims b in
-  let outstring = B64.encode (Buffer.contents b) in
+  match Base64.encode (Buffer.contents b) with
+  | Ok outstring ->
       { ctxt with
         c=
           image
@@ -187,6 +188,8 @@ let paint_image (Coord (x, y)) scale b ({c; _} as ctxt) =
               ; a_xlink_href @@ "data:image/png;base64," ^ outstring ]
             []
           :: c }
+  | Error (`Msg err) ->
+      raise (Base64Exception err)
 
 let get_context () = {d= (0, 0); c= []; colors= None}