diff --git a/utils/generate-command-code.py b/utils/generate-command-code.py
index b5847c469..ce1128e06 100755
--- a/utils/generate-command-code.py
+++ b/utils/generate-command-code.py
@@ -252,11 +252,11 @@ class ReplySchema(object):
         self.schema = {}
         if desc.get("type") == "object":
             if desc.get("properties") and desc.get("additionalProperties") is None:
-                print(f"{self.name}: Any object that has properties should have the additionalProperties field")
+                print("%s: Any object that has properties should have the additionalProperties field" % {self.name})
                 exit(1)
         elif desc.get("type") == "array":
             if desc.get("items") and isinstance(desc["items"], list) and any([desc.get(k) is None for k in ["minItems", "maxItems"]]):
-                print(f"{self.name}: Any array that has items should have the minItems and maxItems fields")
+                print("%s: Any array that has items should have the minItems and maxItems fields" % {self.name})
                 exit(1)
         for k, v in desc.items():
             if isinstance(v, dict):
@@ -543,8 +543,8 @@ if check_command_error_counter != 0:
     exit(1)
 
 commands_filename = "commands_with_reply_schema" if args.with_reply_schema else "commands"
-print(f"Generating {commands_filename}.c...")
-with open(f"{srcdir}/{commands_filename}.c", "w") as f:
+print("Generating %s.c..." % {commands_filename})
+with open("%s/%s.c" % (srcdir, commands_filename), "w") as f:
     f.write("/* Automatically generated by %s, do not edit. */\n\n" % os.path.basename(__file__))
     f.write("#include \"server.h\"\n")
     f.write(