diff --git a/alt-ergo-lib.opam b/alt-ergo-lib.opam
index d5bc5202a..623bc3d8a 100644
--- a/alt-ergo-lib.opam
+++ b/alt-ergo-lib.opam
@@ -21,16 +21,16 @@ depends: [
   "dolmen_type" {>= "0.9"}
   "dolmen_loop" {>= "0.9"}
   "ocplib-simplex" {>= "0.5"}
-  "zarith" {>= "1.4"}
+  "zarith" {>= "1.11"}
   "seq"
   "fmt" {>= "0.9.0"}
   "stdlib-shims"
   "ppx_blob" {>= "0.7.2"}
-  "ppxlib" {>= "0.30.0"}
   "camlzip" {>= "1.07"}
   "odoc" {with-doc}
 ]
 conflicts: [
+  "ppxlib" {< "0.30.0"}
   "result" {< "1.5"}
 ]
 build: [
diff --git a/dune-project b/dune-project
index d6eb80db4..5d87d484c 100644
--- a/dune-project
+++ b/dune-project
@@ -81,16 +81,16 @@ See more details on http://alt-ergo.ocamlpro.com/"
   (dolmen_type (>= 0.9))
   (dolmen_loop (>= 0.9))
   (ocplib-simplex (>= 0.5))
-  (zarith (>= 1.4))
+  (zarith (>= 1.11))
   seq
   (fmt (>= 0.9.0))
   stdlib-shims
   (ppx_blob (>= 0.7.2))
-  (ppxlib (>= 0.30.0))
   (camlzip (>= 1.07))
   (odoc :with-doc)
  )
  (conflicts
+  (ppxlib (< 0.30.0))
   (result (< 1.5))
  )
 )