diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 3aa2ef7a..0d8854c6 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -16,4 +16,4 @@ repos:
     rev: v3.20.0
     hooks:
       - id: pyupgrade
-        args: [ --py36-plus ]
+        args: [ --py39-plus ]
diff --git a/src/instruments/dressler/cesar_1312.py b/src/instruments/dressler/cesar_1312.py
index ef8b13ad..b635827f 100644
--- a/src/instruments/dressler/cesar_1312.py
+++ b/src/instruments/dressler/cesar_1312.py
@@ -102,7 +102,7 @@ def retries(self) -> int:
         return self._retries
 
     @retries.setter
-    def retries(self, value: int) -> Tuple[int, int, bytes]:
+    def retries(self, value: int) -> tuple[int, int, bytes]:
         if value < 0:
             raise ValueError("Retries must be greater than or equal to 0.")
         self._retries = value
@@ -317,7 +317,7 @@ def sendcmd(self, pkg: bytes) -> None:
             raise ValueError("No data received from the device.")
 
     def _make_data(
-        self, length: Union[int, List[int]], data: Union[int, List[int]]
+        self, length: Union[int, list[int]], data: Union[int, list[int]]
     ) -> bytes:
         """Create the data bytes for the package.
 
@@ -397,7 +397,7 @@ def _pack_header(self, data_length: int):
         return (self._address << 3) + data_length
 
     @staticmethod
-    def _unpack_header(hdr: bytes) -> Tuple[int]:
+    def _unpack_header(hdr: bytes) -> tuple[int]:
         """Parse the header and return address and data length.
 
         :param bytes hdr: The header byte.