diff --git a/README.md b/README.md
index dc01952..7ef9005 100644
--- a/README.md
+++ b/README.md
@@ -228,8 +228,8 @@ them to a local data structure.
 
 Logging Blocked Imports
 -----------------------
-To see which modules Vext is blocking set VEXT_LOG_BLOCKS instead of
-standard ImportErrors, you will get ones like this:
+To see which modules Vext is blocking set VEXT_LOG_BLOCKS. Instead of
+standard ModuleNotFoundErrors, you will get ones like this:
 
 
 ```bash
@@ -237,7 +237,7 @@ $ VEXT_LOG_BLOCKS=1
 ```
 ```python
 >>> import pyaudio
-ImportError("Vext blocked import of pyaudio")
+ModuleNotFoundError("Vext blocked import of pyaudio")
 ```
 
 Remembering Blocked Imports
@@ -252,7 +252,7 @@ vext.remember_blocks to True:
 >>> vext.blocked_imports
 set([])
 >>> import pygtk
-ImportError:
+ModuleNotFoundError:
 >>> vext.blocked_imports
 set(["pygtk"])
 ```
@@ -281,4 +281,3 @@ Thanks
 ruamel/venvgtk - for showing something like this is possible
 
 pymotw article on modules and imports
-
diff --git a/setup.py b/setup.py
index 34f885f..74bb785 100644
--- a/setup.py
+++ b/setup.py
@@ -329,6 +329,7 @@ def run(self):
         'vext.install',
     ],
 
+    python_requires=">=3.6",
     setup_requires=["setuptools>=18.0.1", "pip>=1.5.6"],
     install_requires=["ruamel.yaml>=0.11.10"],
 
diff --git a/vext/gatekeeper/__init__.py b/vext/gatekeeper/__init__.py
index a61cec1..8374a6b 100644
--- a/vext/gatekeeper/__init__.py
+++ b/vext/gatekeeper/__init__.py
@@ -184,7 +184,7 @@ def __init__(self, module_info, sitedir):
     def load_module(self, name):
         """
         Only lets modules in allowed_modules be loaded, others
-        will get an ImportError
+        will get a ModuleNotFoundError (a type of ImportError)
         """
 
         # Get the name relative to SITEDIR ..
@@ -198,10 +198,10 @@ def load_module(self, name):
             if remember_blocks:
                 blocked_imports.add(fullname)
             if log_blocks:
-                raise ImportError("Vext blocked import of '%s'" % modulename)
+                raise ModuleNotFoundError("Vext blocked import of '%s'" % modulename)
             else:
                 # Standard error message
-                raise ImportError("No module named %s" % modulename)
+                raise ModuleNotFoundError("No module named %s" % modulename)
 
         if name not in sys.modules:
             try:
@@ -229,7 +229,7 @@ def __init__(self, path_entry):
         except Exception as e:
             sys.stderr.write("Vext disabled:  There was an issue getting the system site packages.\n")
             raise ImportError()
-        
+
         if path_entry in (sitedir, GatekeeperFinder.PATH_TRIGGER):
             logger.debug("handle entry %s", path_entry)
             return