diff --git a/mitmproxy/addonmanager.py b/mitmproxy/addonmanager.py
index 645f3a934..4214d6ea5 100644
--- a/mitmproxy/addonmanager.py
+++ b/mitmproxy/addonmanager.py
@@ -42,7 +42,7 @@ def safecall():
         yield
     except (exceptions.AddonHalt, exceptions.OptionsError):
         raise
-    except Exception as e:
+    except Exception:
         etype, value, tb = sys.exc_info()
         tb = cut_traceback(tb, "invoke_addon")
         ctx.log.error(
diff --git a/mitmproxy/addons/core.py b/mitmproxy/addons/core.py
index 0322b4ce6..a908dbb31 100644
--- a/mitmproxy/addons/core.py
+++ b/mitmproxy/addons/core.py
@@ -53,7 +53,7 @@ class Core:
         if "body_size_limit" in updated:
             try:
                 human.parse_size(opts.body_size_limit)
-            except ValueError as e:
+            except ValueError:
                 raise exceptions.OptionsError(
                     "Invalid body size limit specification: %s" %
                     opts.body_size_limit
diff --git a/mitmproxy/addons/proxyauth.py b/mitmproxy/addons/proxyauth.py
index f8fc344a7..abdc1eacf 100644
--- a/mitmproxy/addons/proxyauth.py
+++ b/mitmproxy/addons/proxyauth.py
@@ -152,7 +152,7 @@ class ProxyAuth:
                     p = ctx.options.proxyauth[1:]
                     try:
                         self.htpasswd = passlib.apache.HtpasswdFile(p)
-                    except (ValueError, OSError) as v:
+                    except (ValueError, OSError):
                         raise exceptions.OptionsError(
                             "Could not open htpasswd file: %s" % p
                         )
diff --git a/mitmproxy/addons/view.py b/mitmproxy/addons/view.py
index 1c8bd0cee..8d27840f5 100644
--- a/mitmproxy/addons/view.py
+++ b/mitmproxy/addons/view.py
@@ -103,7 +103,7 @@ orders = [
 ]
 
 
-class View(collections.Sequence):
+class View(collections.abc.Sequence):
     def __init__(self):
         super().__init__()
         self._store = collections.OrderedDict()
@@ -638,7 +638,7 @@ class Focus:
             self.flow = flow
 
 
-class Settings(collections.Mapping):
+class Settings(collections.abc.Mapping):
     def __init__(self, view: View) -> None:
         self.view = view
         self._values: typing.MutableMapping[str, typing.Dict] = {}
diff --git a/mitmproxy/master.py b/mitmproxy/master.py
index ecb8090bb..e5683356b 100644
--- a/mitmproxy/master.py
+++ b/mitmproxy/master.py
@@ -84,13 +84,14 @@ class Master:
         exc = None
         try:
             loop()
-        except Exception as e:  # pragma: no cover
+        except Exception:  # pragma: no cover
             exc = traceback.format_exc()
         finally:
             if not self.should_exit.is_set():  # pragma: no cover
                 self.shutdown()
             loop = asyncio.get_event_loop()
-            for p in asyncio.Task.all_tasks():
+            tasks = asyncio.all_tasks(loop) if sys.version_info >= (3, 7) else asyncio.Task.all_tasks(loop)
+            for p in tasks:
                 p.cancel()
             loop.close()
 
diff --git a/mitmproxy/proxy/protocol/http2.py b/mitmproxy/proxy/protocol/http2.py
index eae7f06d9..42b61f4d2 100644
--- a/mitmproxy/proxy/protocol/http2.py
+++ b/mitmproxy/proxy/protocol/http2.py
@@ -642,7 +642,7 @@ class Http2SingleStreamLayer(httpbase._HttpTransmissionLayer, basethread.BaseThr
 
         try:
             layer()
-        except exceptions.Http2ZombieException as e:  # pragma: no cover
+        except exceptions.Http2ZombieException:  # pragma: no cover
             pass
         except exceptions.ProtocolException as e:  # pragma: no cover
             self.log(repr(e), "info")
diff --git a/mitmproxy/tools/_main.py b/mitmproxy/tools/_main.py
index 8baaa1c45..f1c763b2b 100644
--- a/mitmproxy/tools/_main.py
+++ b/mitmproxy/tools/_main.py
@@ -134,7 +134,7 @@ def run(
     except exceptions.OptionsError as e:
         print("%s: %s" % (sys.argv[0], e), file=sys.stderr)
         sys.exit(1)
-    except (KeyboardInterrupt, RuntimeError) as e:
+    except (KeyboardInterrupt, RuntimeError):
         pass
     return master
 
diff --git a/release/cibuild.py b/release/cibuild.py
index ba17ced27..820606398 100755
--- a/release/cibuild.py
+++ b/release/cibuild.py
@@ -279,7 +279,7 @@ class BuildEnviron:
             if self.tag.startswith("v"):
                 try:
                     parver.Version.parse(self.tag[1:], strict=True)
-                except parver.ParseError as e:
+                except parver.ParseError:
                     return self.tag
                 return self.tag[1:]
             return self.tag
diff --git a/release/docker/Dockerfile b/release/docker/Dockerfile
index 7c9a24212..258bccf59 100644
--- a/release/docker/Dockerfile
+++ b/release/docker/Dockerfile
@@ -21,7 +21,8 @@ RUN addgroup -S mitmproxy && adduser -S -G mitmproxy mitmproxy \
         openssl-dev \
         python3 \
         python3-dev \
-    && python3 -m ensurepip \
+    && python3 -m ensurepip --upgrade \
+    && pip3 install -U pip \
     && LDFLAGS=-L/lib pip3 install -U /home/mitmproxy/${WHEEL_BASENAME_MITMPROXY} \
     && apk del --purge \
         git \
diff --git a/release/docker/DockerfileARMv7 b/release/docker/DockerfileARMv7
index 6e04b7ad7..40f10edef 100644
--- a/release/docker/DockerfileARMv7
+++ b/release/docker/DockerfileARMv7
@@ -23,7 +23,8 @@ RUN addgroup -S mitmproxy && adduser -S -G mitmproxy mitmproxy \
         openssl-dev \
         python3 \
         python3-dev \
-    && python3 -m ensurepip \
+    && python3 -m ensurepip --upgrade \
+    && pip3 install -U pip \
     && LDFLAGS=-L/lib pip3 install -U /home/mitmproxy/${WHEEL_BASENAME_MITMPROXY} \
     && apk del --purge \
         git \
diff --git a/setup.cfg b/setup.cfg
index 173166d13..83144c22d 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,7 +1,7 @@
 [flake8]
 max-line-length = 140
 max-complexity = 25
-ignore = E251,C901,W503,W292,E722,E741
+ignore = E251,E252,C901,W292,W503,W504,W605,E722,E741
 exclude = mitmproxy/contrib/*,test/mitmproxy/data/*,release/build/*,mitmproxy/io/proto/*
 addons = file,open,basestring,xrange,unicode,long,cmp
 
diff --git a/setup.py b/setup.py
index f3e0312e6..5833ce38a 100644
--- a/setup.py
+++ b/setup.py
@@ -65,7 +65,7 @@ setup(
         "brotlipy>=0.7.0,<0.8",
         "certifi>=2015.11.20.1",  # no semver here - this should always be on the last release!
         "click>=6.2, <7",
-        "cryptography>=2.1.4,<2.4",
+        "cryptography>=2.1.4,<2.5",
         "h2>=3.0.1,<4",
         "hyperframe>=5.1.0,<6",
         "kaitaistruct>=0.7,<0.9",
@@ -74,9 +74,9 @@ setup(
         "protobuf>=3.6.0, <3.7",
         "pyasn1>=0.3.1,<0.5",
         "pyOpenSSL>=17.5,<18.1",
-        "pyparsing>=2.1.3, <2.3",
-        "pyperclip>=1.6.0, <1.7",
-        "ruamel.yaml>=0.13.2, <0.15.55",
+        "pyparsing>=2.1.3,<2.4",
+        "pyperclip>=1.6.0,<1.8",
+        "ruamel.yaml>=0.15,<0.16",
         "sortedcontainers>=1.5.4,<2.1",
         "tornado>=4.3,<5.2",
         "urwid>=2.0.1,<2.1",
@@ -88,7 +88,7 @@ setup(
         ],
         'dev': [
             "asynctest>=0.12.0",
-            "flake8>=3.5, <3.6",
+            "flake8>=3.5,<3.7",
             "Flask>=1.0,<1.1",
             "mypy>=0.590,<0.591",
             "parver>=0.1,<2.0",
@@ -97,9 +97,9 @@ setup(
             "pytest-faulthandler>=1.3.1,<2",
             "pytest-timeout>=1.2.1,<2",
             "pytest-xdist>=1.22,<2",
-            "pytest>=3.3,<4",
+            "pytest>=4.0,<5",
             "requests>=2.9.1, <3",
-            "tox>=3.0,<3.2",
+            "tox>=3.5,<3.6",
             "rstcheck>=2.2, <4.0",
         ],
         'examples': [
diff --git a/test/mitmproxy/addons/test_readfile.py b/test/mitmproxy/addons/test_readfile.py
index 3d28d8b7d..94e18cdb3 100644
--- a/test/mitmproxy/addons/test_readfile.py
+++ b/test/mitmproxy/addons/test_readfile.py
@@ -30,8 +30,8 @@ def data():
 
 
 @pytest.fixture
-def corrupt_data():
-    f = data()
+def corrupt_data(data):
+    f = io.BytesIO(data.getvalue())
     f.seek(0, io.SEEK_END)
     f.write(b"qibble")
     f.seek(0)
diff --git a/test/mitmproxy/net/http/test_headers.py b/test/mitmproxy/net/http/test_headers.py
index e8eb31d31..8fc8b027f 100644
--- a/test/mitmproxy/net/http/test_headers.py
+++ b/test/mitmproxy/net/http/test_headers.py
@@ -75,7 +75,7 @@ class TestHeaders:
 
     def test_replace_multi(self):
         headers = self._2host()
-        headers.replace(r"Host: example\.com", r"Host: example.de")
+        headers.replace(r"Host: example.com", r"Host: example.de")
         assert headers.get_all("Host") == ["example.de", "example.org"]
 
     def test_replace_remove_spacer(self):
diff --git a/test/mitmproxy/test_http.py b/test/mitmproxy/test_http.py
index 49e61e25a..8a299d8e7 100644
--- a/test/mitmproxy/test_http.py
+++ b/test/mitmproxy/test_http.py
@@ -49,7 +49,7 @@ class TestHTTPRequest:
         r.path = "path/foo"
         r.headers["Foo"] = "fOo"
         r.content = b"afoob"
-        assert r.replace("foo(?i)", "boo") == 4
+        assert r.replace("(?i)foo", "boo") == 4
         assert r.path == "path/boo"
         assert b"foo" not in r.content
         assert r.headers["boo"] == "boo"
@@ -82,7 +82,7 @@ class TestHTTPResponse:
         r = http.HTTPResponse.wrap(mitmproxy.test.tutils.tresp())
         r.headers["Foo"] = "fOo"
         r.content = b"afoob"
-        assert r.replace("foo(?i)", "boo") == 3
+        assert r.replace("(?i)foo", "boo") == 3
         assert b"foo" not in r.content
         assert r.headers["boo"] == "boo"
 
diff --git a/tox.ini b/tox.ini
index 9401b8f26..85cf40aaf 100644
--- a/tox.ini
+++ b/tox.ini
@@ -44,8 +44,8 @@ commands =
 passenv = TRAVIS_* APPVEYOR_* AWS_* TWINE_* DOCKER_* RTOOL_KEY WHEEL DOCKER PYINSTALLER WININSTALLER
 deps =
   -rrequirements.txt
-  pyinstaller==3.3.1
-  twine==1.11.0
+  pyinstaller==3.4
+  twine==1.12.1
   awscli
 commands =
   mitmdump --version