diff --git a/eio_main.opam b/eio_main.opam
index c6298237d..42b22f01b 100644
--- a/eio_main.opam
+++ b/eio_main.opam
@@ -14,8 +14,8 @@ depends: [
   "kcas" {>= "0.3.0" & with-test}
   "yojson" {>= "2.0.2" & with-test}
   "eio_linux" {= version & os = "linux"}
-  "eio_posix" {= version & os-family != "windows"}
-  "eio_windows" {= version & os-family = "windows"}
+  "eio_posix" {= version & os != "win32"}
+  "eio_windows" {= version & os = "win32"}
   "odoc" {with-doc}
 ]
 build: [