diff --git a/.gitignore b/.gitignore
index 0fb72b7..f02c938 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,2 @@
 # dune files
 _build
-*.opam
diff --git a/dune-project b/dune-project
index aefb866..93d4099 100644
--- a/dune-project
+++ b/dune-project
@@ -1,9 +1,10 @@
-(lang dune 3.4)
+(lang dune 3.8)
 (name hello)
 (license MIT-0)
 
 ; https://dune.readthedocs.io/en/stable/opam.html#generating-opam-files
-(generate_opam_files true)
+(generate_opam_files)
+(opam_file_location inside_opam_directory)
 
 (cram enable)
 
diff --git a/flake.nix b/flake.nix
index bb74951..a208d13 100644
--- a/flake.nix
+++ b/flake.nix
@@ -54,10 +54,6 @@
             ];
 
             strictDeps = true;
-
-            preBuild = ''
-              dune build hello.opam
-            '';
           };
         });
 
diff --git a/opam/hello.opam b/opam/hello.opam
new file mode 100644
index 0000000..3668d64
--- /dev/null
+++ b/opam/hello.opam
@@ -0,0 +1,22 @@
+# This file is generated by dune, edit dune-project instead
+opam-version: "2.0"
+synopsis: "Friendly greetings"
+license: "MIT-0"
+depends: [
+  "dune" {>= "3.8"}
+  "odoc" {with-doc}
+]
+build: [
+  ["dune" "subst"] {dev}
+  [
+    "dune"
+    "build"
+    "-p"
+    name
+    "-j"
+    jobs
+    "@install"
+    "@runtest" {with-test}
+    "@doc" {with-doc}
+  ]
+]