diff --git a/alt-ergo-lib.opam b/alt-ergo-lib.opam
index e9f397319..a2d48a46d 100644
--- a/alt-ergo-lib.opam
+++ b/alt-ergo-lib.opam
@@ -20,7 +20,7 @@ depends: [
   "dolmen" {>= "0.10"}
   "dolmen_type" {>= "0.10"}
   "dolmen_loop" {>= "0.10"}
-  "ocplib-simplex" {>= "0.5"}
+  "ocplib-simplex" {>= "0.5.1"}
   "zarith" {>= "1.11"}
   "seq"
   "fmt" {>= "0.9.0"}
diff --git a/alt-ergo-lib.opam.locked b/alt-ergo-lib.opam.locked
index 350ae7593..0def9a7a8 100644
--- a/alt-ergo-lib.opam.locked
+++ b/alt-ergo-lib.opam.locked
@@ -47,7 +47,7 @@ depends: [
   "ocamlbuild" {= "0.14.2"}
   "ocamlfind" {= "1.9.6"}
   "ocplib-endian" {= "1.2"}
-  "ocplib-simplex" {= "0.5"}
+  "ocplib-simplex" {= "0.5.1"}
   "pp_loc" {= "2.1.0"}
   "ppx_blob" {= "0.7.2"}
   "ppx_derivers" {= "1.2.1"}
@@ -57,7 +57,6 @@ depends: [
   "seq" {= "base"}
   "sexplib0" {= "v0.16.0"}
   "spelll" {= "0.4"}
-  "stdlib-shims" {= "0.3.0"}
   "stdcompat" {= "19"}
   "topkg" {= "1.0.7"}
   "uutf" {= "1.0.3"}
diff --git a/dune-project b/dune-project
index f6c6d47e9..080b1bae9 100644
--- a/dune-project
+++ b/dune-project
@@ -80,7 +80,7 @@ See more details on http://alt-ergo.ocamlpro.com/"
   (dolmen (>= 0.10))
   (dolmen_type (>= 0.10))
   (dolmen_loop (>= 0.10))
-  (ocplib-simplex (>= 0.5))
+  (ocplib-simplex (>= 0.5.1))
   (zarith (>= 1.11))
   seq
   (fmt (>= 0.9.0))
diff --git a/nix/sources.json b/nix/sources.json
index 2272b7bd2..eb51c5aa9 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -25,17 +25,17 @@
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "ocplib-simplex": {
-        "branch": "v0.5",
+        "branch": "v0.5.1",
         "description": "A library implementing a simplex algorithm, in a functional style, for solving systems of linear inequalities",
         "homepage": "",
         "owner": "OCamlPro",
         "repo": "ocplib-simplex",
-        "rev": "9b0944c81088b9039775e48cdbc3499128ca3692",
-        "sha256": "1dxx68k2smnxrp9b8snpvi74d41yfxn2j6swbqnny6r1d1950bmk",
+        "rev": "12e7c1fd994d4c40cf7159008a67579f470df616",
+        "sha256": "0jkyqvcia4950cr1ip4n4xnjgaqlliljw48b40n95j75wjvy3d3w",
         "type": "tarball",
-        "url": "https://github.com/OCamlPro/ocplib-simplex/archive/9b0944c81088b9039775e48cdbc3499128ca3692.tar.gz",
+        "url": "https://github.com/OCamlPro/ocplib-simplex/archive/12e7c1fd994d4c40cf7159008a67579f470df616.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz",
-        "version": "0.5"
+        "version": "0.5.1"
     },
     "pp_loc": {
         "branch": "v2.1.0",