diff --git a/GT.opam b/GT.opam
index db534f9b..bd7c2774 100644
--- a/GT.opam
+++ b/GT.opam
@@ -23,7 +23,7 @@ homepage: "https://github.com/PLTools/GT"
 bug-reports: "https://github.com/PLTools/GT/issues"
 depends: [
   "ppxlib" {<= "0.32.1"}
-  "ocaml" {>= "4.13"}
+  "ocaml" {>= "4.13" & < "5.0.0" | >= "5.2.0" & < "5.3.0"}
   "camlp5" {>= "8.00.05"}
   "dune" {>= "2.8"}
   "ocamlfind" {build}
diff --git a/Makefile b/Makefile
index e6e5e924..1e2d802d 100644
--- a/Makefile
+++ b/Makefile
@@ -27,7 +27,7 @@ promote:
 
 celan: clean
 clean:
-	$(RM) -r _build
+	$(RM) -r _build _coverage
 
 rebuild: clean
 	$(MAKE) all tests
diff --git a/dune-project b/dune-project
index 973caf5c..7e423af6 100644
--- a/dune-project
+++ b/dune-project
@@ -27,7 +27,13 @@
   (ppxlib
    (<= "0.32.1"))
   (ocaml
-   (>= "4.13"))
+   (or
+    (and
+     (>= "4.13")
+     (< "5.0.0"))
+    (and
+     (>= "5.2.0")
+     (< "5.3.0"))))
   (camlp5
    (>= "8.00.05"))
   dune