diff --git a/ocaml/trexio/read_json.py b/ocaml/trexio/read_json.py
index d41bc00..c65e553 100755
--- a/ocaml/trexio/read_json.py
+++ b/ocaml/trexio/read_json.py
@@ -7,6 +7,21 @@ stubs_file= "trexio_stubs.c"
 ml_file   = "trexio.ml"
 mli_file  = ml_file+"i"
 
+def check_version():
+   with open('trexio.opam','r') as f:
+      for line in f:
+         if line.startswith("version"):
+            ocaml_version = line.split(':')[1].strip()[1:-1]
+            break
+   with open('../../configure.ac','r') as f:
+      for line in f:
+         if line.startswith("AC_INIT"):
+            trexio_version = line.split(',')[1].strip()[1:-1]
+            break
+   if ocaml_version != trexio_version:
+      print(f"Inconsistent versions:\nTREXIO:{trexio_version}\nOCaml: {ocaml_version}\n")
+      raise
+
 def write_stubs(data):
 
     with open("src/"+stubs_file,'r') as f:
@@ -643,6 +658,7 @@ def write_ml(data):
 
 def main():
 
+    check_version()
     with open(json_file,'r') as f:
         data = json.load(f)
         for group in data:
diff --git a/ocaml/trexio/trexio.opam b/ocaml/trexio/trexio.opam
index d3a6a46..f38dc69 100644
--- a/ocaml/trexio/trexio.opam
+++ b/ocaml/trexio/trexio.opam
@@ -1,6 +1,6 @@
 # This file is generated by dune, edit dune-project instead
 opam-version: "2.0"
-version: "2.3.2"
+version: "2.4.0"
 synopsis: "Binding for the TREXIO Input/Output library"
 description:
   "TREXIO is a file format and library for storing wave functions and integrals for quantum chemistry."
diff --git a/rust/trexio/build.py b/rust/trexio/build.py
index 8e6aa89..2b17df2 100755
--- a/rust/trexio/build.py
+++ b/rust/trexio/build.py
@@ -1,9 +1,29 @@
 #!/usr/bin/env python3
 
-def main():
+json_file = "../../trex.json"
+trexio_h = "../../include/trexio.h"
+
+def check_version():
+   with open('Cargo.toml','r') as f:
+      for line in f:
+         if line.startswith("version"):
+            rust_version = line.split('=')[1].strip()[1:-1]
+            break
+   with open('../../configure.ac','r') as f:
+      for line in f:
+         if line.startswith("AC_INIT"):
+            trexio_version = line.split(',')[1].strip()[1:-1]
+            break
+   if rust_version != trexio_version:
+      print(f"Inconsistent versions:\nTREXIO:{trexio_version}\nRust:  {rust_version}\n")
+      raise
+
+
+
+def make_interface():
     err = {}
     be  = {}
-    with open("../../include/trexio.h", 'r') as f:
+    with open(trexio_h, 'r') as f:
         for line in f:
             buf = line.lstrip()
 
@@ -11,7 +31,7 @@ def main():
             if buf.startswith("#define TREXIO_") and "(trexio_exit_code)" in buf :
                 buf2 = buf.replace(")","").replace("(","").split()
                 err[buf2[1]] = int(buf2[3].strip())
-                
+
             # Get backends
             if buf.startswith("#define TREXIO_") and "(back_end_t)" in buf :
                 buf2 = buf.replace(")","").replace("(","").split()
@@ -33,7 +53,12 @@ def main():
         f.write(f"#undef TREXIO_AUTO;\n")
         f.write(f"const back_end_t TREXIO_AUTO = TREXIO_INVALID_BACK_END;\n")
 
-    
+
+
+def make_functions():
+  pass
 
 if __name__ == '__main__':
-   main()
+   check_version()
+   make_interface()
+   make_functions()