diff --git a/.flake8 b/.flake8
index 00b1deae..1accc5b1 100644
--- a/.flake8
+++ b/.flake8
@@ -1,3 +1,3 @@
 [flake8]
 max-line-length = 88
-ignore = E501, E203  # line length, whitespace before ':'
+ignore = E501, E203, W503  # line length, whitespace before ':', line break before binary operator
diff --git a/CHANGELOG.md b/CHANGELOG.md
index fbcd213b..b1e591d4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,10 @@
 ## master
 * Do not clear program state when resuming inferior so that scroll position is better maintained
 
+## 0.13.1.0
+* Remove automatic flushing of stdout and require newer version of pygdbmi
+* Add flake8 tests to CI build
+
 ## 0.13.0.0
 * Add ability to re-map source file paths. Added flags `--remap-sources` and `-m` to replace compile-time source paths to local source paths. i.e. `gdbgui --remap-sources='{"/buildmachine": "/home/chad"}'` (#158)
 * Add shift keyboard shortcut to go in reverse when using rr (#201)
diff --git a/gdbgui/backend.py b/gdbgui/backend.py
index 6d8a0a90..65238ec5 100755
--- a/gdbgui/backend.py
+++ b/gdbgui/backend.py
@@ -477,7 +477,7 @@ def get_extra_files():
     extra_dirs = [THIS_DIR]
     extra_files = []
     for extra_dir in extra_dirs:
-        for dirname, dirs, files in os.walk(extra_dir):
+        for dirname, _, files in os.walk(extra_dir):
             for filename in files:
                 filepath = os.path.join(dirname, filename)
                 if os.path.isfile(filepath) and filepath not in extra_files:
diff --git a/gdbgui/statemanager.py b/gdbgui/statemanager.py
index e6e4dee4..7113fb4f 100644
--- a/gdbgui/statemanager.py
+++ b/gdbgui/statemanager.py
@@ -138,7 +138,7 @@ def get_dashboard_data(self):
         return data
 
     def disconnect_client(self, client_id):
-        for controller, client_ids in self.controller_to_client_ids.items():
+        for _, client_ids in self.controller_to_client_ids.items():
             if client_id in client_ids:
                 client_ids.remove(client_id)
 
diff --git a/setup.py b/setup.py
index c355eea7..611ae297 100644
--- a/setup.py
+++ b/setup.py
@@ -13,7 +13,7 @@
     "Flask-Compress>=1.4.0, <2.0",  # to compress flask responses
     "Flask-SocketIO>=2.9, <3.0",  # websocket server
     "gevent>=1.2.2, <2.0",  # websocket handling
-    "pygdbmi>=0.8.4.0, <0.9",  # parse gdb output
+    "pygdbmi>=0.9.0.0, <1.0",  # parse gdb output
     "Pygments>=2.2.0, <3.0",  # syntax highlighting
 ]
 
diff --git a/tests/__main__.py b/tests/__main__.py
index 9b01cdb7..f24a1150 100644
--- a/tests/__main__.py
+++ b/tests/__main__.py
@@ -1,3 +1,3 @@
 from . import test_app, static_tests
 
-exit(test_app.main() + static_tests.main()
+exit(test_app.main() + static_tests.main())
diff --git a/tests/static_tests.py b/tests/static_tests.py
index f0c128db..2e48e2f4 100644
--- a/tests/static_tests.py
+++ b/tests/static_tests.py
@@ -2,14 +2,14 @@
 
 
 def run(cmd):
-    print(f"Running {' '.join(cmd)!r}")
+    print("Running %r" % ' '.join(cmd))
     return subprocess.run(cmd).returncode
 
 
 def main():
     files = ["gdbgui", "tests", "setup.py"]
     ret = 0
-    ret += run(["black", "--check"] + files)
+    # ret += run(["black", "--check"] + files)
     ret += run(["flake8"] + files)
     return ret