diff --git a/aws-s3-async.opam b/aws-s3-async.opam
index 03470ba..b67ccd0 100644
--- a/aws-s3-async.opam
+++ b/aws-s3-async.opam
@@ -17,8 +17,8 @@ depends: [
   "async_kernel" {>= "v0.9.0"}
   "async_unix" {>= "v0.9.0"}
   "conduit-async" {>= "4.0.0"}
-  "core" {>= "v0.14.0"}
-  "core_unix" {>= "v0.14.0"}
+  "core" {>= "v0.15.0"}
+  "core_unix" {>= "v0.15.0"}
 ]
 synopsis: "Ocaml library for accessing Amazon S3 - Async version"
 description: """