Added error checking for python version & clarified README

README.rst

@@ -22,11 +22,8 @@ Supported Python versions:
 
 * Python 3.6 (and later)
 
-If you need Python 2 support, ``atrcopy`` 6.5 and earlier supports:
-
-* Python 2.7
-* Python 3.5
-* Python 3.6
+If you need Python 2 support, ``atrcopy`` 6.5 and earlier supports Python 2.7,
+which you can install with ``pip install "atrcopy<7.0"``
 
 Dependencies
 ------------

scripts/atrcopy

@@ -1,6 +1,12 @@
 #!/usr/bin/env python
 
 if __name__ == "__main__":
+    import sys
+    if sys.version_info < (3, 6, 0):
+        print("atrcopy requires Python 3.6 or greater to run; this is Python %s" % ".".join([str(v) for v in sys.version_info[0:2]]))
+        if sys.version_info[0] == 2:
+            print("Python 2 support was dropped with atrcopy 7.0, so you can either use:\n\n    pip install \"atrcopy<7.0\"\n\nto install a version compatible with Python 2, or install Python 3.6 or higher.")
+    else:
         import atrcopy
     
         atrcopy.run()

setup.py

@@ -33,6 +33,7 @@ setup(name="atrcopy",
             "Topic :: Software Development :: Libraries",
             "Topic :: Utilities",
         ],
+        python_requires = '>=3.6',
         install_requires = [
             'numpy',
         ],