diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index c8b17b05..963504a6 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -55,8 +55,11 @@ jobs:
       # temporary until it's in a release
       - run: opam pin https://github.com/ocaml-multicore/picos.git -y -n
 
+      - run: opam pin -y -n lwt 5.9.2
       - run: opam install -t moonpool moonpool-lwt --deps-only
       - run: opam exec -- dune build @install
+
       # install some depopts
+      - run: opam pin -y -n lwt 6.1.1
       - run: opam install thread-local-storage trace domain-local-await
       - run: opam exec -- dune build --profile=release --force @install @runtest
diff --git a/src/lwt/dune b/src/lwt/dune
index c6bb5ab3..e9a94982 100644
--- a/src/lwt/dune
+++ b/src/lwt/dune
@@ -3,8 +3,20 @@
  (public_name moonpool-lwt)
  (enabled_if
   (>= %{ocaml_version} 5.0))
+ (modules moonpool_lwt types_)
  (libraries
   (re_export moonpool)
   picos
   (re_export lwt)
   lwt.unix))
+
+(executable
+ (name gen_types_)
+ (modules gen_types_))
+
+(rule
+ (enabled_if %{lib-available:lwt})
+ (deps types_.ml.5 types_.ml.6)
+ (target types_.ml)
+ (action
+  (run ./gen_types_.exe %{version:lwt})))
diff --git a/src/lwt/gen_types_.ml b/src/lwt/gen_types_.ml
new file mode 100644
index 00000000..771f0e97
--- /dev/null
+++ b/src/lwt/gen_types_.ml
@@ -0,0 +1,23 @@
+let copy_file src dst =
+  let ic = open_in src in
+  let oc = open_out dst in
+  let buf = Bytes.create 1024 in
+  (try
+     while true do
+       let n = input ic buf 0 (Bytes.length buf) in
+       if n = 0 then raise End_of_file;
+       output oc buf 0 n
+     done
+   with End_of_file -> ());
+  close_in ic;
+  close_out oc
+
+let () =
+  let version = Sys.argv.(1) in
+  let major =
+    try Scanf.sscanf version "%d.%s" (fun maj _ -> maj) with _ -> 0
+  in
+  if major >= 6 then
+    copy_file "types_.ml.6" "types_.ml"
+  else
+    copy_file "types_.ml.5" "types_.ml"
diff --git a/src/lwt/moonpool_lwt.ml b/src/lwt/moonpool_lwt.ml
index 3293f653..35b75908 100644
--- a/src/lwt/moonpool_lwt.ml
+++ b/src/lwt/moonpool_lwt.ml
@@ -23,7 +23,7 @@ module Scheduler_state = struct
     mutable as_runner: Moonpool.Runner.t;
     mutable enter_hook: Lwt_main.Enter_iter_hooks.hook option;
     mutable leave_hook: Lwt_main.Leave_iter_hooks.hook option;
-    mutable notification: int;
+    mutable notification: Types_.notification;
         (** A lwt_unix notification to wake up the event loop *)
     has_notified: bool Atomic.t;
   }
@@ -42,7 +42,7 @@ module Scheduler_state = struct
       as_runner = Moonpool.Runner.dummy;
       enter_hook = None;
       leave_hook = None;
-      notification = 0;
+      notification = Types_.dummy_notification;
       has_notified = Atomic.make false;
     }
 
diff --git a/src/lwt/types_.ml.5 b/src/lwt/types_.ml.5
new file mode 100644
index 00000000..7b75d8ce
--- /dev/null
+++ b/src/lwt/types_.ml.5
@@ -0,0 +1,3 @@
+
+type notification = int
+let dummy_notification : notification = 0
diff --git a/src/lwt/types_.ml.6 b/src/lwt/types_.ml.6
new file mode 100644
index 00000000..0e3eb517
--- /dev/null
+++ b/src/lwt/types_.ml.6
@@ -0,0 +1,3 @@
+
+type notification = Lwt_unix.notification
+let dummy_notification : notification = Lwt_unix.make_notification ignore