diff --git a/ipykernel/connect.py b/ipykernel/connect.py
index 25571649..9ca7867a 100644
--- a/ipykernel/connect.py
+++ b/ipykernel/connect.py
@@ -2,17 +2,21 @@
 """
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
+from __future__ import annotations
 
 import json
 import sys
 from subprocess import PIPE, Popen
-from typing import Any, Dict
+from typing import TYPE_CHECKING, Any
 
 import jupyter_client
 from jupyter_client import write_connection_file
 
+if TYPE_CHECKING:
+    from ipykernel.kernelapp import IPKernelApp
 
-def get_connection_file(app=None):
+
+def get_connection_file(app: IPKernelApp | None = None) -> str:
     """Return the path to the connection file of an app
 
     Parameters
@@ -46,7 +50,7 @@ def _find_connection_file(connection_file):
         return jupyter_client.find_connection_file(connection_file)
 
 
-def get_connection_info(connection_file=None, unpack=False):
+def get_connection_info(connection_file: str | None = None, unpack: bool = False) -> str:
     """Return the connection information for the current Kernel.
 
     Parameters
@@ -82,7 +86,7 @@ def get_connection_info(connection_file=None, unpack=False):
     return info_str
 
 
-def connect_qtconsole(connection_file=None, argv=None):
+def connect_qtconsole(connection_file: str | None = None, argv: list[str] | None = None) -> Popen:
     """Connect a qtconsole to the current kernel.
 
     This is useful for connecting a second qtconsole to a kernel, or to a
@@ -111,13 +115,13 @@ def connect_qtconsole(connection_file=None, argv=None):
 
     cmd = ";".join(["from qtconsole import qtconsoleapp", "qtconsoleapp.main()"])
 
-    kwargs: Dict[str, Any] = {}
+    kwargs: dict[str, Any] = {}
     # Launch the Qt console in a separate session & process group, so
     # interrupting the kernel doesn't kill it.
     kwargs["start_new_session"] = True
 
     return Popen(
-        [sys.executable, "-c", cmd, "--existing", cf, *argv],  # noqa
+        [sys.executable, "-c", cmd, "--existing", cf, *argv],  # noqa: S603
         stdout=PIPE,
         stderr=PIPE,
         close_fds=(sys.platform != "win32"),
diff --git a/ipykernel/kernelspec.py b/ipykernel/kernelspec.py
index 320afff9..eb3ac49e 100644
--- a/ipykernel/kernelspec.py
+++ b/ipykernel/kernelspec.py
@@ -3,6 +3,8 @@
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
+from __future__ import annotations
+
 import errno
 import json
 import os
@@ -10,6 +12,7 @@
 import stat
 import sys
 import tempfile
+from typing import Any
 
 from jupyter_client.kernelspec import KernelSpecManager
 from traitlets import Unicode
@@ -27,7 +30,11 @@
 RESOURCES = pjoin(os.path.dirname(__file__), "resources")
 
 
-def make_ipkernel_cmd(mod="ipykernel_launcher", executable=None, extra_arguments=None):
+def make_ipkernel_cmd(
+    mod: str = "ipykernel_launcher",
+    executable: str | None = None,
+    extra_arguments: list[str] | None = None,
+) -> list[str]:
     """Build Popen command list for launching an IPython kernel.
 
     Parameters
@@ -52,7 +59,7 @@ def make_ipkernel_cmd(mod="ipykernel_launcher", executable=None, extra_arguments
     return arguments
 
 
-def get_kernel_dict(extra_arguments=None):
+def get_kernel_dict(extra_arguments: list[str] | None = None) -> dict[str, Any]:
     """Construct dict for kernel.json"""
     return {
         "argv": make_ipkernel_cmd(extra_arguments=extra_arguments),
@@ -62,7 +69,11 @@ def get_kernel_dict(extra_arguments=None):
     }
 
 
-def write_kernel_spec(path=None, overrides=None, extra_arguments=None):
+def write_kernel_spec(
+    path: str | None = None,
+    overrides: dict[str, Any] | None = None,
+    extra_arguments: list[str] | None = None,
+) -> str:
     """Write a kernel spec directory to `path`
 
     If `path` is not specified, a temporary directory is created.
@@ -93,13 +104,13 @@ def write_kernel_spec(path=None, overrides=None, extra_arguments=None):
 
 
 def install(
-    kernel_spec_manager=None,
-    user=False,
-    kernel_name=KERNEL_NAME,
-    display_name=None,
-    prefix=None,
-    profile=None,
-    env=None,
+    kernel_spec_manager: KernelSpecManager | None = None,
+    user: bool = False,
+    kernel_name: str = KERNEL_NAME,
+    display_name: str | None = None,
+    prefix: str | None = None,
+    profile: str | None = None,
+    env: dict[str, str] | None = None,
 ):
     """Install the IPython kernelspec for Jupyter
 
@@ -167,13 +178,13 @@ class InstallIPythonKernelSpecApp(Application):
 
     name = Unicode("ipython-kernel-install")
 
-    def initialize(self, argv=None):
+    def initialize(self, argv: list[str] | None = None) -> None:
         """Initialize the app."""
         if argv is None:
             argv = sys.argv[1:]
         self.argv = argv
 
-    def start(self):
+    def start(self) -> None:
         """Start the app."""
         import argparse
 
diff --git a/pyproject.toml b/pyproject.toml
index f34c5482..8f9ac894 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -112,12 +112,12 @@ matrix.qt.features = [
 
 [tool.hatch.envs.typing]
 features = ["test"]
-dependencies = ["mypy>=1.5.1", "traitlets>=5.11.2", "ipython>=8.16.1"]
+dependencies = ["mypy>=1.6.0", "traitlets>=5.11.2", "ipython>=8.16.1"]
 [tool.hatch.envs.typing.scripts]
 test = "mypy --install-types --non-interactive {args}"
 
 [tool.hatch.envs.lint]
-dependencies = ["black==23.3.0", "mdformat>0.7", "ruff==0.0.287"]
+dependencies = ["black==23.3.0", "mdformat>0.7", "ruff==0.1.1"]
 detached = true
 [tool.hatch.envs.lint.scripts]
 style = [