diff --git a/google/cloud/sql/connector/connector.py b/google/cloud/sql/connector/connector.py
index 28b42587..132f385a 100755
--- a/google/cloud/sql/connector/connector.py
+++ b/google/cloud/sql/connector/connector.py
@@ -88,7 +88,7 @@ def __init__(
         enable_iam_auth: bool = False,
         timeout: int = 30,
         credentials: Optional[Credentials] = None,
-        loop: asyncio.AbstractEventLoop = None,
+        loop: Optional[asyncio.AbstractEventLoop] = None,
         quota_project: Optional[str] = None,
         sqladmin_api_endpoint: str = "https://sqladmin.googleapis.com",
     ) -> None:
@@ -333,7 +333,7 @@ async def create_async_connector(
     enable_iam_auth: bool = False,
     timeout: int = 30,
     credentials: Optional[Credentials] = None,
-    loop: asyncio.AbstractEventLoop = None,
+    loop: Optional[asyncio.AbstractEventLoop] = None,
 ) -> Connector:
     """
     Create Connector object for asyncio connections that can auto-detect
diff --git a/google/cloud/sql/connector/instance.py b/google/cloud/sql/connector/instance.py
index 8f6ba603..cb693987 100644
--- a/google/cloud/sql/connector/instance.py
+++ b/google/cloud/sql/connector/instance.py
@@ -222,7 +222,7 @@ def __init__(
         loop: asyncio.AbstractEventLoop,
         credentials: Optional[Credentials] = None,
         enable_iam_auth: bool = False,
-        quota_project: str = None,
+        quota_project: Optional[str] = None,
         sqladmin_api_endpoint: str = "https://sqladmin.googleapis.com",
     ) -> None:
         # validate and parse instance connection name
diff --git a/google/cloud/sql/connector/rate_limiter.py b/google/cloud/sql/connector/rate_limiter.py
index 21a3ff74..6698471d 100644
--- a/google/cloud/sql/connector/rate_limiter.py
+++ b/google/cloud/sql/connector/rate_limiter.py
@@ -14,6 +14,7 @@
 limitations under the License.
 """
 import asyncio
+from typing import Optional
 
 
 class AsyncRateLimiter(object):
@@ -41,7 +42,7 @@ def __init__(
         self,
         max_capacity: int = 1,
         rate: float = 1 / 60,
-        loop: asyncio.AbstractEventLoop = None,
+        loop: Optional[asyncio.AbstractEventLoop] = None,
     ) -> None:
         self.rate = rate
         self.max_capacity = max_capacity
diff --git a/noxfile.py b/noxfile.py
index 6b3f55b4..a4beddac 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -23,7 +23,6 @@
 
 BLACK_VERSION = "black==23.12.1"
 ISORT_VERSION = "isort==5.13.2"
-MYPY_VERSION = "mypy==0.982"
 
 LINT_PATHS = ["google", "tests", "noxfile.py", "setup.py"]
 
@@ -40,7 +39,7 @@ def lint(session):
     session.install(
         "flake8",
         "flake8-annotations",
-        MYPY_VERSION,
+        "mypy",
         BLACK_VERSION,
         ISORT_VERSION,
         "types-setuptools",