Index: grammalecte-server.py
==================================================================
--- grammalecte-server.py
+++ grammalecte-server.py
@@ -318,10 +318,13 @@
     if dOptions:
         oGCE.setOptions(dOptions)
 
     # Python version
     print("Python: " + sys.version)
+    if sys.version < "3.7":
+        print("Python 3.7+ required")
+        return
     # Grammalecte
     echo("Grammalecte v{}".format(oGCE.version))
     oGCE.displayOptions()
     # Process Pool Executor
     initExecutor(nMultiCPU)

Index: make.py
==================================================================
--- make.py
+++ make.py
@@ -368,10 +368,13 @@
 
 
 def main ():
     "build Grammalecte with requested options"
     print("Python: " + sys.version)
+    if sys.version < "3.7":
+        print("Python 3.7+ required")
+        return
     xParser = argparse.ArgumentParser()
     xParser.add_argument("lang", type=str, nargs='+', help="lang project to generate (name of folder in /lang)")
     xParser.add_argument("-uc", "--use_cache", help="use data cache instead of rebuilding rules", action="store_true")
     xParser.add_argument("-b", "--build_data", help="launch build_data.py (part 1 and 2)", action="store_true")
     xParser.add_argument("-bb", "--build_data_before", help="launch build_data.py (only part 1: before dictionary building)", action="store_true")