diff --git a/.travis.yml b/.travis.yml
index 75a0a78..333d47a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,10 +2,8 @@ language: python
 matrix:
   fast_finish: true
   include:
-    - python: "3.6"
+    - python: "3.7"
       env: TOXENV=lint
-    - python: "3.6"
-      env: TOXENV=py36
     - python: "3.7"
       env: TOXENV=py37
     - python: "3.8"
diff --git a/setup.py b/setup.py
index 66fc5cc..1ece6a4 100644
--- a/setup.py
+++ b/setup.py
@@ -48,9 +48,11 @@ def is_raspberry_pi(raise_on_errors=False):
     return True
 
 
-requires = ['pyserial-asyncio',
-            'zigpy>=0.20.1.a3',
-            ]
+requires = [
+    'pyserial-asyncio',
+    'zigpy>=0.22.2',
+]
+
 if is_raspberry_pi():
     requires.append('RPi.GPIO')
 
diff --git a/tox.ini b/tox.ini
index f20bfc0..8c390df 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,7 +4,7 @@
 # and then run "tox" from this directory.
 
 [tox]
-envlist = py36, py37, py38, lint
+envlist = py37, py38, lint
 skip_missing_interpreters = True
 
 [testenv]
diff --git a/zigpy_zigate/types.py b/zigpy_zigate/types.py
index af7c2a2..fe50615 100644
--- a/zigpy_zigate/types.py
+++ b/zigpy_zigate/types.py
@@ -129,8 +129,12 @@ def serialize(self):
         return super().serialize()[::-1]
 
 
-class NWK(zigpy.types.HexRepr, uint16_t):
-    pass
+class NWK(uint16_t):
+    def __repr__(self):
+        return "0x{:04x}".format(self)
+
+    def __str__(self):
+        return "0x{:04x}".format(self)
 
 
 class ADDRESS_MODE(uint8_t, enum.Enum):