diff --git a/requirements/dev.txt b/requirements/dev.txt
index 19f427ad3d..5cbbee0118 100644
--- a/requirements/dev.txt
+++ b/requirements/dev.txt
@@ -97,7 +97,7 @@ matrix-client==0.3.2
 mock==2.0.0
 moto==1.3.3
 mypy-extensions==0.4.1
-mypy==0.641
+mypy==0.650
 ndg-httpsclient==0.5.1
 oauth2client==4.1.3
 oauthlib==2.1.0
diff --git a/requirements/mypy.in b/requirements/mypy.in
index d5050267b7..36dfcc813a 100644
--- a/requirements/mypy.in
+++ b/requirements/mypy.in
@@ -2,7 +2,7 @@
 # /tools/update-locked-requirements to update requirements/dev.txt
 # and requirements/mypy.txt.
 # See requirements/README.md for more detail.
-mypy==0.641
+mypy==0.650
 # Include typing explicitly, since it's needed on Python 3.4
 typing==3.6.6
 typing_extensions==3.6.6
diff --git a/requirements/mypy.txt b/requirements/mypy.txt
index 8a805c85dd..e1a5cadb8b 100644
--- a/requirements/mypy.txt
+++ b/requirements/mypy.txt
@@ -8,7 +8,7 @@
 # For details, see requirements/README.md .
 #
 mypy-extensions==0.4.1    # via mypy
-mypy==0.641
+mypy==0.650
 typed-ast==1.1.0          # via mypy
 typing==3.6.6
 typing_extensions==3.6.6
diff --git a/version.py b/version.py
index 42c8dbf4e8..bb537ad938 100644
--- a/version.py
+++ b/version.py
@@ -11,4 +11,4 @@ LATEST_RELEASE_ANNOUNCEMENT = "https://blog.zulip.org/2018/11/07/zulip-1-9-relea
 # Typically, adding a dependency only requires a minor version bump, and
 # removing a dependency requires a major version bump.
 
-PROVISION_VERSION = '26.16'
+PROVISION_VERSION = '26.17'
diff --git a/zerver/lib/exceptions.py b/zerver/lib/exceptions.py
index 0a36000200..9bcaba20e8 100644
--- a/zerver/lib/exceptions.py
+++ b/zerver/lib/exceptions.py
@@ -21,7 +21,7 @@ class AbstractEnum(Enum):
     def value(self) -> None:
         raise AssertionError("Not implemented")
 
-    def __reduce_ex__(self, proto: int) -> NoReturn:
+    def __reduce_ex__(self, proto: object) -> NoReturn:
         raise AssertionError("Not implemented")
 
 class ErrorCode(AbstractEnum):