diff --git a/cohttp-lwt-jsoo.opam b/cohttp-lwt-jsoo.opam
index 7a18e7d95a..820c2b1530 100644
--- a/cohttp-lwt-jsoo.opam
+++ b/cohttp-lwt-jsoo.opam
@@ -27,13 +27,9 @@ depends: [
   "cohttp" {>= "1.0.0"}
   "cohttp-lwt" {>= "1.0.0"}
   "lwt" {>= "3.0.0"}
-  "js_of_ocaml" {>= "3.0"}
-  "js_of_ocaml-ppx" {>= "3.0"}
-  "js_of_ocaml-lwt"
-]
-conflicts: [
-  "lwt" {< "2.5.0"}
-  "js_of_ocaml" {< "2.8"}
+  "js_of_ocaml" {>= "3.3.0"}
+  "js_of_ocaml-ppx" {>= "3.3.0"}
+  "js_of_ocaml-lwt" {>= "3.3.0"}
 ]
 build: [
   ["dune" "subst"] {pinned}
diff --git a/cohttp-lwt-jsoo/src/cohttp_lwt_xhr.ml b/cohttp-lwt-jsoo/src/cohttp_lwt_xhr.ml
index 6d4e5c10be..42878f88b5 100644
--- a/cohttp-lwt-jsoo/src/cohttp_lwt_xhr.ml
+++ b/cohttp-lwt-jsoo/src/cohttp_lwt_xhr.ml
@@ -15,6 +15,7 @@
  *
   }}}*)
 
+open Js_of_ocaml
 module C = Cohttp
 module CLB = Cohttp_lwt.Body
 
diff --git a/cohttp-lwt-jsoo/src/cohttp_lwt_xhr.mli b/cohttp-lwt-jsoo/src/cohttp_lwt_xhr.mli
index 65c5f3364c..cba8e13c14 100644
--- a/cohttp-lwt-jsoo/src/cohttp_lwt_xhr.mli
+++ b/cohttp-lwt-jsoo/src/cohttp_lwt_xhr.mli
@@ -27,7 +27,7 @@ module type Params = sig
 
   (** JavaScript string to OCaml conversion.  [Js.to_bytestring] or
       [Js.to_string] *)
-  val convert_body_string : Js.js_string Js.t -> string
+  val convert_body_string : Js_of_ocaml.Js.js_string Js_of_ocaml.Js.t -> string
 
   (** Whether withCredentials property of XHR is set. *)
   val with_credentials : bool
diff --git a/cohttp.opam b/cohttp.opam
index 88b59de664..31f77cf669 100644
--- a/cohttp.opam
+++ b/cohttp.opam
@@ -41,7 +41,7 @@ depends: [
   "ppx_fields_conv" {>= "v0.9.0"}
   "ppx_sexp_conv" {>= "v0.9.0"}
   "stringext"
-  "base64" {>= "2.0.0"}
+  "base64" {>= "2.0.0" & <"3.0.0"}
   "fmt" {with-test}
   "jsonm" {build}
   "alcotest" {with-test}