diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index f5dbfc4508bb95718a118d7552b01b5aa7b600d9..254f7fadc17f92855af435144c37303826d431a7 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -16,7 +16,6 @@ tests:
   - opam repository add remote https://opam.ocaml.org
   - opam depext --yes ocplib-endian base fmt alt-ergo.2.4.0
   - opam install . --deps-only --with-test --yes
-  - opam install alt-ergo.2.4.0 --yes
   - make
   - make test
   tags:
diff --git a/caisar.opam b/caisar.opam
index a472d8d330c713cb0e9127f749a16fb998e0ff18..333b2f1232e591cdc23162021d07e9ce18ebda54 100644
--- a/caisar.opam
+++ b/caisar.opam
@@ -4,15 +4,15 @@ version: "0.1"
 synopsis: "Framework for neural network verification"
 depends: [
   "ocaml" {>= "4.13.0"}
-  "dune-site" {>= "2.9.0"}
+  "dune-site" {= "2.9.0"}
   "piqi" {>= "0.7.6"}
   "piqilib" {>= "0.6.14"}
   "zarith" {>= "1.7"}
   "ocplib-endian" {>= "1.0"}
-  "dune" {>= "2.9" & >= "2.7.1"}
+  "dune" {>= "2.9" & >= "2.7.1" & <= "2.9.0"}
   "base" {>= "v0.14.0"}
   "stdio" {>= "v0.14.0"}
-  "cmdliner" {>= "1.0.4"}
+  "cmdliner" {= "1.0.4"}
   "fmt" {>= "0.8.9"}
   "logs" {>= "0.7.0"}
   "ppx_deriving" {>= "5.1"}
@@ -26,7 +26,7 @@ depends: [
   "odoc" {with-doc}
 ]
 build: [
-  ["dune" "subst"] {dev}
+  ["dune" "subst" "--root" "."] {dev}
   [
     "dune"
     "build"
@@ -34,7 +34,8 @@ build: [
     name
     "-j"
     jobs
-    "--promote-install-files=false"
+    "--promote-install-files"
+    "false"
     "@install"
     "@runtest" {with-test}
     "@doc" {with-doc}
diff --git a/dune-project b/dune-project
index e059691fc41a0b1493359e469096b799f58d0fe3..c7418cdacc4586bd4f72247876a5518ea6790f6b 100644
--- a/dune-project
+++ b/dune-project
@@ -14,15 +14,15 @@
   (synopsis "Framework for neural network verification")
   (depends
    (ocaml (>= 4.13.0))
-   (dune-site (>= 2.9.0))
+   (dune-site (= 2.9.0))
    (piqi (>= 0.7.6))
    (piqilib (>= 0.6.14))
    (zarith (>= 1.7))
    (ocplib-endian (>= 1.0))
-   (dune (>= 2.7.1))
+   (dune (and (>= 2.7.1) (<= 2.9.0)))
    (base (>= v0.14.0))
    (stdio (>= v0.14.0))
-   (cmdliner (>= 1.0.4))
+   (cmdliner (= 1.0.4))
    (fmt (>= 0.8.9))
    (logs (>= 0.7.0))
    (ppx_deriving (>= 5.1))
@@ -44,8 +44,8 @@
   (name nnet)
   (synopsis "NNet parser")
   (depends
-   (ocaml (>= 4.10))
-   (dune (>= 2.9.1))
+   (ocaml (>= 4.13))
+   (dune (and (>= 2.7.1) (<= 2.9.0)))
    (base (>= v0.14.0))
   )
 )
@@ -54,8 +54,8 @@
   (name onnx)
   (synopsis "ONNX parser")
   (depends
-   (ocaml (>= 4.10))
-   (dune (>= 2.9.1))
+   (ocaml (>= 4.13))
+   (dune (and (>= 2.7.1) (<= 2.9.0)))
    (base (>= v0.14.0))
    (ocaml-protoc-plugin (= 4.2.0))
   )
diff --git a/nnet.opam b/nnet.opam
index aa2ffd8b08b83e5d09134e0904ee1293c9d9959a..cebe3b828f2fb4127523ad2030e9d46361152799 100644
--- a/nnet.opam
+++ b/nnet.opam
@@ -3,13 +3,13 @@ opam-version: "2.0"
 version: "0.1"
 synopsis: "NNet parser"
 depends: [
-  "ocaml" {>= "4.10"}
-  "dune" {>= "2.9" & >= "2.9.1"}
+  "ocaml" {>= "4.13"}
+  "dune" {>= "2.9" & >= "2.7.1" & <= "2.9.0"}
   "base" {>= "v0.14.0"}
   "odoc" {with-doc}
 ]
 build: [
-  ["dune" "subst"] {dev}
+  ["dune" "subst" "--root" "."] {dev}
   [
     "dune"
     "build"
@@ -17,7 +17,8 @@ build: [
     name
     "-j"
     jobs
-    "--promote-install-files=false"
+    "--promote-install-files"
+    "false"
     "@install"
     "@runtest" {with-test}
     "@doc" {with-doc}
diff --git a/onnx.opam b/onnx.opam
index 1440f206e7b77aecba8249d0490dd381388aa5ce..7301915e905d357253411839863d81e5b53d27fb 100644
--- a/onnx.opam
+++ b/onnx.opam
@@ -3,14 +3,14 @@ opam-version: "2.0"
 version: "0.1"
 synopsis: "ONNX parser"
 depends: [
-  "ocaml" {>= "4.10"}
-  "dune" {>= "2.9" & >= "2.9.1"}
+  "ocaml" {>= "4.13"}
+  "dune" {>= "2.9" & >= "2.7.1" & <= "2.9.0"}
   "base" {>= "v0.14.0"}
   "ocaml-protoc-plugin" {= "4.2.0"}
   "odoc" {with-doc}
 ]
 build: [
-  ["dune" "subst"] {dev}
+  ["dune" "subst" "--root" "."] {dev}
   [
     "dune"
     "build"
@@ -18,7 +18,8 @@ build: [
     name
     "-j"
     jobs
-    "--promote-install-files=false"
+    "--promote-install-files"
+    "false"
     "@install"
     "@runtest" {with-test}
     "@doc" {with-doc}