diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
index 70d8f519..18966419 100644
--- a/.github/workflows/check.yml
+++ b/.github/workflows/check.yml
@@ -33,7 +33,7 @@ jobs:
         # stop the build if there are Python syntax errors or undefined names
         flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
         # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
-        flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+        flake8 . --count --exit-zero --max-complexity=15 --statistics
     - name: Test with pytest
       run: |
         pytest
diff --git a/ably/util/crypto.py b/ably/util/crypto.py
index 1f428a89..df2d0072 100644
--- a/ably/util/crypto.py
+++ b/ably/util/crypto.py
@@ -171,4 +171,6 @@ def validate_cipher_params(cipher_params):
         key_length = cipher_params.key_length
         if key_length == 128 or key_length == 256:
             return
-        raise ValueError('Unsupported key length ' + str(key_length) + ' for aes-cbc encryption. Encryption key must be 128 or 256 bits (16 or 32 ASCII characters)')
+        raise ValueError(
+            'Unsupported key length %s for aes-cbc encryption. Encryption key must be 128 or 256 bits'
+            ' (16 or 32 ASCII characters)' % key_length)
diff --git a/setup.cfg b/setup.cfg
index b2a36bfa..d95ce934 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,7 +1,9 @@
 [coverage:run]
 branch=True
+
 [flake8]
-max-line-length = 120
-ignore = E114,E121,E123,E126,E127,E128,E241,E226,E231,E251,E302,E305,E306,E402,E501,F401,F821,F841,I100,I101,I201,N802,W291,W293,W391,W503,W504
+max-line-length = 115
+ignore = E114,E121,E123,E126,E127,E128,E241,E226,E231,E251,E302,E305,E306,E402,F401,F821,F841,I100,I101,I201,N802,W291,W293,W391,W503,W504
+
 [tool:pytest]
 #log_level = DEBUG
diff --git a/test/ably/restcrypto_test.py b/test/ably/restcrypto_test.py
index 2aff5803..63657674 100644
--- a/test/ably/restcrypto_test.py
+++ b/test/ably/restcrypto_test.py
@@ -74,10 +74,17 @@ def test_crypto_publish(self):
         message_contents = dict((m.name, m.data) for m in messages)
         log.debug("message_contents: %s" % str(message_contents))
 
-        assert "This is a string message payload" == message_contents["publish3"], "Expect publish3 to be expected String)"
-        assert b"This is a byte[] message payload" == message_contents["publish4"], "Expect publish4 to be expected byte[]. Actual: %s" % str(message_contents['publish4'])
-        assert {"test": "This is a JSONObject message payload"} == message_contents["publish5"], "Expect publish5 to be expected JSONObject"
-        assert ["This is a JSONArray message payload"] == message_contents["publish6"], "Expect publish6 to be expected JSONObject"
+        assert "This is a string message payload" == message_contents["publish3"],\
+               "Expect publish3 to be expected String)"
+
+        assert b"This is a byte[] message payload" == message_contents["publish4"],\
+               "Expect publish4 to be expected byte[]. Actual: %s" % str(message_contents['publish4'])
+
+        assert {"test": "This is a JSONObject message payload"} == message_contents["publish5"],\
+               "Expect publish5 to be expected JSONObject"
+
+        assert ["This is a JSONArray message payload"] == message_contents["publish6"],\
+               "Expect publish6 to be expected JSONObject"
 
     def test_crypto_publish_256(self):
         rndfile = Random.new()
@@ -100,10 +107,17 @@ def test_crypto_publish_256(self):
         message_contents = dict((m.name, m.data) for m in messages)
         log.debug("message_contents: %s" % str(message_contents))
 
-        assert "This is a string message payload" == message_contents["publish3"], "Expect publish3 to be expected String)"
-        assert b"This is a byte[] message payload" == message_contents["publish4"], "Expect publish4 to be expected byte[]. Actual: %s" % str(message_contents['publish4'])
-        assert {"test": "This is a JSONObject message payload"} == message_contents["publish5"], "Expect publish5 to be expected JSONObject"
-        assert ["This is a JSONArray message payload"] == message_contents["publish6"], "Expect publish6 to be expected JSONObject"
+        assert "This is a string message payload" == message_contents["publish3"],\
+               "Expect publish3 to be expected String)"
+
+        assert b"This is a byte[] message payload" == message_contents["publish4"],\
+               "Expect publish4 to be expected byte[]. Actual: %s" % str(message_contents['publish4'])
+
+        assert {"test": "This is a JSONObject message payload"} == message_contents["publish5"],\
+               "Expect publish5 to be expected JSONObject"
+
+        assert ["This is a JSONArray message payload"] == message_contents["publish6"],\
+               "Expect publish6 to be expected JSONObject"
 
     def test_crypto_publish_key_mismatch(self):
         channel_name = self.get_channel_name('persisted:crypto_publish_key_mismatch')
@@ -146,10 +160,17 @@ def test_crypto_send_unencrypted(self):
         message_contents = dict((m.name, m.data) for m in messages)
         log.debug("message_contents: %s" % str(message_contents))
 
-        assert "This is a string message payload" == message_contents["publish3"], "Expect publish3 to be expected String)"
-        assert b"This is a byte[] message payload" == message_contents["publish4"], "Expect publish4 to be expected byte[]. Actual: %s" % str(message_contents['publish4'])
-        assert {"test": "This is a JSONObject message payload"} == message_contents["publish5"], "Expect publish5 to be expected JSONObject"
-        assert ["This is a JSONArray message payload"] == message_contents["publish6"], "Expect publish6 to be expected JSONObject"
+        assert "This is a string message payload" == message_contents["publish3"],\
+               "Expect publish3 to be expected String"
+
+        assert b"This is a byte[] message payload" == message_contents["publish4"],\
+               "Expect publish4 to be expected byte[]. Actual: %s" % str(message_contents['publish4'])
+
+        assert {"test": "This is a JSONObject message payload"} == message_contents["publish5"],\
+               "Expect publish5 to be expected JSONObject"
+
+        assert ["This is a JSONArray message payload"] == message_contents["publish6"],\
+               "Expect publish6 to be expected JSONObject"
 
     def test_crypto_encrypted_unhandled(self):
         channel_name = self.get_channel_name('persisted:crypto_send_encrypted_unhandled')
diff --git a/test/ably/restinit_test.py b/test/ably/restinit_test.py
index 6d61dc43..eccc09c0 100644
--- a/test/ably/restinit_test.py
+++ b/test/ably/restinit_test.py
@@ -123,17 +123,20 @@ def test_specified_realtime_host(self):
     @dont_vary_protocol
     def test_specified_port(self):
         ably = AblyRest(token='foo', port=9998, tls_port=9999)
-        assert 9999 == Defaults.get_port(ably.options), "Unexpected port mismatch. Expected: 9999. Actual: %d" % ably.options.tls_port
+        assert 9999 == Defaults.get_port(ably.options),\
+               "Unexpected port mismatch. Expected: 9999. Actual: %d" % ably.options.tls_port
 
     @dont_vary_protocol
     def test_specified_non_tls_port(self):
         ably = AblyRest(token='foo', port=9998, tls=False)
-        assert 9998 == Defaults.get_port(ably.options), "Unexpected port mismatch. Expected: 9999. Actual: %d" % ably.options.tls_port
+        assert 9998 == Defaults.get_port(ably.options),\
+               "Unexpected port mismatch. Expected: 9999. Actual: %d" % ably.options.tls_port
 
     @dont_vary_protocol
     def test_specified_tls_port(self):
         ably = AblyRest(token='foo', tls_port=9999, tls=True)
-        assert 9999 == Defaults.get_port(ably.options), "Unexpected port mismatch. Expected: 9999. Actual: %d" % ably.options.tls_port
+        assert 9999 == Defaults.get_port(ably.options),\
+               "Unexpected port mismatch. Expected: 9999. Actual: %d" % ably.options.tls_port
 
     @dont_vary_protocol
     def test_tls_defaults_to_true(self):
diff --git a/test/ably/utils.py b/test/ably/utils.py
index f72b8e46..4677b0a5 100644
--- a/test/ably/utils.py
+++ b/test/ably/utils.py
@@ -62,7 +62,10 @@ def test_decorated(self, *args, **kwargs):
             patcher = patch()
             fn(self, *args, **kwargs)
             unpatch(patcher)
-            assert len(responses) >= 1, "If your test doesn't make any requests, use the @dont_vary_protocol decorator"
+
+            assert len(responses) >= 1,\
+                   "If your test doesn't make any requests, use the @dont_vary_protocol decorator"
+
             for response in responses:
                 if protocol == 'json':
                     assert response.headers['content-type'] == 'application/json'