diff --git a/dune-project b/dune-project
index 589d83f8..25179505 100644
--- a/dune-project
+++ b/dune-project
@@ -86,7 +86,7 @@
   printbox
   printbox-text
   ocannl_npy
-  angstrom
+  (angstrom (>= 0.15))
   stdio
   num
   ppxlib
diff --git a/neural_nets_lib.opam b/neural_nets_lib.opam
index e626bce9..eb1ee06b 100644
--- a/neural_nets_lib.opam
+++ b/neural_nets_lib.opam
@@ -21,7 +21,7 @@ depends: [
   "printbox"
   "printbox-text"
   "ocannl_npy"
-  "angstrom"
+  "angstrom" {>= "0.15"}
   "stdio"
   "num"
   "ppxlib"