diff --git a/src/setup.py b/src/setup.py
index <HASH>..<HASH> 100644
--- a/src/setup.py
+++ b/src/setup.py
@@ -38,7 +38,7 @@ setup(name='supy',
           'f90nml',
           'matplotlib',
           'seaborn',
-          'supy_driver>=2018b15'  # a separate f2py-based driver
+          'supy_driver>=2018b16'  # a separate f2py-based driver
       ],
       include_package_data=True,
       test_suite='nose.collector',
diff --git a/src/supy/version.py b/src/supy/version.py
index <HASH>..<HASH> 100644
--- a/src/supy/version.py
+++ b/src/supy/version.py
@@ -2,7 +2,7 @@
 
 ver_milestone = 2018
 ver_major = 12
-ver_minor = 15
+ver_minor = 21
 ver_remark = ''
 __version__ = '{ver_milestone}.{ver_major}.{ver_minor}{ver_remark}'.format(
     ver_milestone=ver_milestone,
loosened python requirement to <I>