diff --git a/bin/ipie b/bin/ipie
index b01f0208..7a1c8d24 100755
--- a/bin/ipie
+++ b/bin/ipie
@@ -1,4 +1,3 @@
-
 # Copyright 2022 The ipie Developers. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -20,12 +19,9 @@
 #!/usr/bin/env python3
 
 import argparse
-import json
 import sys
 
-from ipie.config import MPI
-
-from ipie.config import config
+from ipie.config import config, MPI
 
 
 def parse_args(args, comm):
@@ -43,10 +39,12 @@ def parse_args(args, comm):
     """
 
     if comm.rank == 0:
-        parser = argparse.ArgumentParser(description = __doc__)
-        parser.add_argument('--gpu', dest='use_gpu', action="store_true",
-                            help='Use GPU.')
-        parser.add_argument('remaining_options', nargs=argparse.REMAINDER)
+        parser = argparse.ArgumentParser(description=__doc__)
+        parser.add_argument("--gpu", dest="use_gpu", action="store_true", help="Use GPU.")
+        parser.add_argument(
+            "--legacy", dest="use_legacy", action="store_true", help="Use legacy driver."
+        )
+        parser.add_argument("remaining_options", nargs=argparse.REMAINDER)
         options = parser.parse_args(args)
     else:
         options = None
@@ -60,7 +58,6 @@ def parse_args(args, comm):
     return options
 
 
-
 def main(input_file):
     """Simple launcher for ipie via input file.
 
@@ -72,11 +69,21 @@ def main(input_file):
     comm = MPI.COMM_WORLD
     options = parse_args(sys.argv[1:], comm)
     config.update_option("use_gpu", options.use_gpu)
-    from ipie.qmc.calc import setup_calculation
-    (afqmc, comm) = setup_calculation(options.remaining_options[0])
-    afqmc.run(verbose=True)
-    afqmc.finalise(verbose=True)
+    if options.use_legacy:
+        from ipie.legacy.qmc.calc import get_driver as get_legacy_driver
+        from ipie.qmc.calc import read_input
+
+        input_dict = read_input(options.remaining_options[0], comm)
+        afqmc = get_legacy_driver(input_dict, comm)
+        afqmc.run(comm=comm)
+        afqmc.finalise(comm)
+    else:
+        from ipie.qmc.calc import setup_calculation
+
+        (afqmc, comm) = setup_calculation(options.remaining_options[0])
+        afqmc.run(verbose=True)
+        afqmc.finalise(verbose=True)
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     main(sys.argv[1])