diff --git a/opam b/opam
index 3a9128ee..bb5a53f9 100644
--- a/opam
+++ b/opam
@@ -26,6 +26,6 @@ depends: [
   "easy-format"
   "ulex"
   "xmlm"
-  "base64" {>="2.0.0"}
+  "base64" {>="3.1.0"}
 ]
 dev-repo: "git://github.com/alavrik/piqi"
diff --git a/piqilib/piqi_base64.ml b/piqilib/piqi_base64.ml
index c5a6ae73..a98346e8 100644
--- a/piqilib/piqi_base64.ml
+++ b/piqilib/piqi_base64.ml
@@ -18,12 +18,11 @@
 (* TODO: add more base64 validation; the base64 library doesn't do any
  * validation *)
 let decode x =
-  try
-    B64.decode x
-  with _ ->
-    invalid_arg "Piqi_base64.decode"
+  match Base64.decode x with
+  | Error _ -> invalid_arg "Piqi_base64.decode"
+  | Ok v -> v
 
 
 let encode x =
-  B64.encode x
+  Base64.encode_exn x