diff --git a/plexpy/config.py b/plexpy/config.py
index 7b583d8d..6f2926d9 100644
--- a/plexpy/config.py
+++ b/plexpy/config.py
@@ -177,6 +177,7 @@ _CONFIG_DEFINITIONS = {
     'NOTIFY_RECENTLY_ADDED_UPGRADE': (int, 'Monitoring', 0),
     'NOTIFY_REMOTE_ACCESS_THRESHOLD': (int, 'Monitoring', 60),
     'NOTIFY_CONCURRENT_BY_IP': (int, 'Monitoring', 0),
+    'NOTIFY_CONCURRENT_IPV6_CIDR': (str, 'Monitoring', '/64'),
     'NOTIFY_CONCURRENT_THRESHOLD': (int, 'Monitoring', 2),
     'NOTIFY_NEW_DEVICE_INITIAL_ONLY': (int, 'Monitoring', 1),
     'NOTIFY_SERVER_CONNECTION_THRESHOLD': (int, 'Monitoring', 60),
@@ -536,7 +537,7 @@ class Config(object):
         Returns something from the ini unless it is a real property
         of the configuration object or is not all caps.
         """
-        if not re.match(r'[A-Z_]+$', name):
+        if not re.match(r'[A-Z0-9_]+$', name):
             return super(Config, self).__getattr__(name)
         else:
             return self.check_setting(name)
diff --git a/plexpy/helpers.py b/plexpy/helpers.py
index 9cfb9c45..085dfc12 100644
--- a/plexpy/helpers.py
+++ b/plexpy/helpers.py
@@ -33,6 +33,7 @@ from functools import reduce, wraps
 import hashlib
 import imghdr
 from future.moves.itertools import islice, zip_longest
+from ipaddress import ip_address, ip_network, IPv4Address
 import ipwhois
 import ipwhois.exceptions
 import ipwhois.utils
@@ -1777,3 +1778,18 @@ def check_watched(media_type, view_offset, duration, marker_credits_first=None,
 
 def pms_name():
     return plexpy.CONFIG.PMS_NAME_OVERRIDE or plexpy.CONFIG.PMS_NAME
+
+
+def ip_type(ip: str) -> str:
+    try:
+        return "IPv4" if type(ip_address(ip)) is IPv4Address else "IPv6"
+    except ValueError:
+        return "Invalid"
+
+
+def get_ipv6_network_address(ip: str) -> str:
+    cidr = "/64"
+    cidr_pattern = re.compile(r'^/(1([0-1]\d|2[0-8]))$|^/(\d\d)$|^/[1-9]$')
+    if cidr_pattern.match(plexpy.CONFIG.NOTIFY_CONCURRENT_IPV6_CIDR):
+        cidr = plexpy.CONFIG.NOTIFY_CONCURRENT_IPV6_CIDR
+    return str(ip_network(ip+cidr, strict=False).network_address)
diff --git a/plexpy/notification_handler.py b/plexpy/notification_handler.py
index 7dd81627..8b4b8583 100644
--- a/plexpy/notification_handler.py
+++ b/plexpy/notification_handler.py
@@ -160,6 +160,7 @@ def add_notifier_each(notifier_id=None, notify_action=None, stream_data=None, ti
 
 def notify_conditions(notify_action=None, stream_data=None, timeline_data=None, **kwargs):
     logger.debug("Tautulli NotificationHandler :: Checking global notification conditions.")
+    evaluated = False
 
     # Activity notifications
     if stream_data:
@@ -187,7 +188,13 @@ def notify_conditions(notify_action=None, stream_data=None, timeline_data=None,
                 user_sessions = [s for s in result['sessions'] if s['user_id'] == stream_data['user_id']]
 
             if plexpy.CONFIG.NOTIFY_CONCURRENT_BY_IP:
-                evaluated = len(Counter(s['ip_address'] for s in user_sessions)) >= plexpy.CONFIG.NOTIFY_CONCURRENT_THRESHOLD
+                ip_addresses = set()
+                for s in user_sessions:
+                    if helpers.ip_type(s['ip_address']) == 'IPv6':
+                        ip_addresses.add(helpers.get_ipv6_network_address(s['ip_address']))
+                    elif helpers.ip_type(s['ip_address']) == 'IPv4':
+                        ip_addresses.add(s['ip_address'])
+                evaluated = len(ip_addresses) >= plexpy.CONFIG.NOTIFY_CONCURRENT_THRESHOLD
             else:
                 evaluated = len(user_sessions) >= plexpy.CONFIG.NOTIFY_CONCURRENT_THRESHOLD