diff --git a/colibrics.opam b/colibrics.opam
index 7fd8ae3acededf85b234a9c4eaddc533e9c24b45..9e8bb4a44be4a9229d9176ac79c6ed4a55788f3f 100644
--- a/colibrics.opam
+++ b/colibrics.opam
@@ -16,7 +16,7 @@ depends: [
   "zarith" {>= "1.12"}
   "cmdliner" {>= "1.1.1"}
   "ocaml" {>= "4.08"}
-  "core" {>= "v0.14.1"}
+  "core" {>= "v0.14.1" & < "v0.16.0"}
   "jingoo" {>= "1.4.4"}
   "logs" {>= "0.7.0"}
   "why3" {>= "1.4.0"}
diff --git a/dune-project b/dune-project
index 2d28d31dc9ab1860aa8bbad583c3351ade0ad10a..27fd3f9206daef79e19a5f1238308e3b5e66edcc 100644
--- a/dune-project
+++ b/dune-project
@@ -26,7 +26,7 @@
     ("zarith" (>= "1.12"))
     ("cmdliner" (>= 1.1.1))
     ("ocaml" (>= "4.08"))
-    ("core" (>= "v0.14.1"))
+    ("core" (and (>= "v0.14.1") (< "v0.16.0")))
     ("jingoo" (>= "1.4.4"))
     ("logs" (>= "0.7.0"))
     ("why3" (>= "1.4.0"))