diff --git a/CHANGES.md b/CHANGES.md
index bf53af8..efa1a32 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,8 +1,11 @@
 Next release
 ------------
 
-- Use dune.3.18 support to generate `x-maintenance-intent` entry
-- Patch `ppx_yojson_conv` dependency which was missing a `v`-prefix
+- Support ppxlib 0.37 and 0.38 and require dune.3.22.0 #49
+- Adjust test suite to be compatible with >= dune.3.22.0 #48
+- Switch to using `ppx_deriving_yojson` instead of `ppx_yojson_conv` #47
+- Use dune.3.18 support to generate `x-maintenance-intent` entry #45
+- Patch `ppx_yojson_conv` dependency which was missing a `v`-prefix #43
 - Introduce a `mutaml.opam.template` to avoid opam linting failure #41
 - Adjust RE to support `runtest` on OpenBSD too #40
 - Remove `which` and `conf-which` dependency #39
diff --git a/dune-project b/dune-project
index 8417d91..3daa0b8 100644
--- a/dune-project
+++ b/dune-project
@@ -1,4 +1,4 @@
-(lang dune 3.18)
+(lang dune 3.22)
 
 (name mutaml)
 
@@ -28,9 +28,8 @@
  (tags ("test" "mutation testing"))
  (depends
   (ocaml (>= 4.12.0))
-  (dune (>= 3.18))
-  (dune (and (>= 3.22.0) :with-test))
-  (ppxlib (and (>= 0.28.0) (< 0.36.0)))
+  (ocaml (and (< 5.2.0) :with-test))
+  (ppxlib (>= 0.37.0))
   (ppx_deriving_yojson (>= 3.7.0))
   stdlib-random
   conf-timeout
diff --git a/mutaml.opam b/mutaml.opam
index 4758bf7..6449790 100644
--- a/mutaml.opam
+++ b/mutaml.opam
@@ -17,10 +17,10 @@ homepage: "https://github.com/jmid/mutaml"
 doc: "https://github.com/jmid/mutaml"
 bug-reports: "https://github.com/jmid/mutaml/issues"
 depends: [
+  "dune" {>= "3.22"}
   "ocaml" {>= "4.12.0"}
-  "dune" {>= "3.18"}
-  "dune" {>= "3.22.0" & with-test}
-  "ppxlib" {>= "0.28.0" & < "0.36.0"}
+  "ocaml" {< "5.2.0" & with-test}
+  "ppxlib" {>= "0.37.0"}
   "ppx_deriving_yojson" {>= "3.7.0"}
   "stdlib-random"
   "conf-timeout"
diff --git a/src/ppx/mutaml_ppx.ml b/src/ppx/mutaml_ppx.ml
index 0071e5d..c6a73f1 100644
--- a/src/ppx/mutaml_ppx.ml
+++ b/src/ppx/mutaml_ppx.ml
@@ -463,10 +463,13 @@ class mutate_mapper (rs : RS.t) =
         self#mutaml_mutant ctx loc(*e0.pexp_loc*) [%expr ()] e0' (string_of_exp e1) in
       { e0 with pexp_desc = Pexp_sequence (e0'',e1') }
 
-    | _, Pexp_function cases ->
-      self#cases ctx cases >>| fun cases_pure -> (* all cases are pure in 'function' *)
-      let function_ = { e with pexp_desc = Pexp_function cases_pure } in
-      if Match.cases_contain_matching_patterns cases_pure
+    | _, Pexp_function (params, constrs, fbody) ->
+      self#function_body ctx fbody >>| fun fbody ->
+      let function_ = { e with pexp_desc = Pexp_function (params, constrs, fbody) } in
+      let contains_matching_patterns = (match fbody with
+          | Pfunction_body _ -> false
+          | Pfunction_cases (cases_pure,_,_) -> Match.cases_contain_matching_patterns cases_pure) in
+      if contains_matching_patterns
       then
         Exp.attr function_ (* disable pattern-match warning *)
           { attr_name = {txt = "ocaml.warning"; loc};
@@ -489,6 +492,14 @@ class mutate_mapper (rs : RS.t) =
     | _ ->
       super#expression ctx e
 
+  method! function_body ctx body = match body with
+    | Pfunction_body e ->
+      self#expression ctx e >>| fun e ->
+      Pfunction_body e
+    | Pfunction_cases (cases,loc,attrs) ->
+      self#cases ctx cases >>| fun cases_pure -> (* all cases are pure in 'function' *)
+      Pfunction_cases (cases_pure,loc,attrs)
+
   (* don't mutate attribute parameters such as 'false' in [@@deriving show {with_path=false}] *)
   method! attributes _ctx attrs = return attrs
 
diff --git a/test/instrumentation-tests/function-merge-consecutive.t b/test/instrumentation-tests/function-merge-consecutive.t
index cbc8d2c..e0d3bc8 100644
--- a/test/instrumentation-tests/function-merge-consecutive.t
+++ b/test/instrumentation-tests/function-merge-consecutive.t
@@ -658,18 +658,19 @@ Same example that triggers merge-of-consecutive-patterns w/GADTs false
     | X 
     | Lit of int 
     | Binop of aexp * binop * aexp 
-  let rec interpret xval =
-    ((function
-      | X -> xval
-      | Lit i -> i
-      | Binop (ae0, Add, ae1) when not (__is_mutaml_mutant__ "test:2") ->
-          let v0 = interpret xval ae0 in
-          let v1 = interpret xval ae1 in
-          if __is_mutaml_mutant__ "test:0" then v0 - v1 else v0 + v1
-      | Binop (ae0, Add, ae1) | Binop (ae0, Mul, ae1) ->
-          let v0 = interpret xval ae0 in
-          let v1 = interpret xval ae1 in
-          if __is_mutaml_mutant__ "test:1" then v0 + v1 else v0 * v1)
+  let rec interpret =
+    ((fun xval ->
+        function
+       | X -> xval
+       | Lit i -> i
+       | Binop (ae0, Add, ae1) when not (__is_mutaml_mutant__ "test:2") ->
+           let v0 = interpret xval ae0 in
+           let v1 = interpret xval ae1 in
+           if __is_mutaml_mutant__ "test:0" then v0 - v1 else v0 + v1
+       | Binop (ae0, Add, ae1) | Binop (ae0, Mul, ae1) ->
+           let v0 = interpret xval ae0 in
+           let v1 = interpret xval ae1 in
+           if __is_mutaml_mutant__ "test:1" then v0 + v1 else v0 * v1)
     [@ocaml.warning "-8"])
   let () =
     (interpret (if __is_mutaml_mutant__ "test:3" then 3 else 2)
diff --git a/test/negative-tests/ppx-negtests.t b/test/negative-tests/ppx-negtests.t
index be77ab1..b206b32 100644
--- a/test/negative-tests/ppx-negtests.t
+++ b/test/negative-tests/ppx-negtests.t
@@ -269,6 +269,8 @@ Instrument and check that it was received
     -dont-apply <names>         Exclude these transformations
     -cookie NAME=EXPR           Set the cookie NAME to EXPR
     --cookie                    Same as -cookie
+    -raise-embedded-errors      Raise the first embedded error found in the processed AST
+    -allow-deriving-end         Whether to allow [@@@deriving.end], which will soon be deprecated.
     -seed                       Set randomness seed for mutaml's instrumentation
     -mut-rate                   Set probability in % of mutating a syntax tree node (default: 50%)
     -gadt                       Allow only pattern mutations compatible with GADTs (default: true)