diff --git a/bumble/snoop.py b/bumble/snoop.py
index 5a8262c..686bf9d 100644
--- a/bumble/snoop.py
+++ b/bumble/snoop.py
@@ -64,7 +64,7 @@ class BtSnooper(Snooper):
     Snooper that saves HCI packets using the BTSnoop format, based on RFC 1761.
     """
 
-    IDENTIFICATION_PATTERN = b'btsnoop\0'
+    IDENTIFICATION_PATTERN = b"btsnoop\0"
     TIMESTAMP_ANCHOR = datetime.datetime(2000, 1, 1)
     TIMESTAMP_DELTA = 0x00E03AB44A676000
     ONE_MS = datetime.timedelta(microseconds=1)
@@ -74,7 +74,7 @@ class BtSnooper(Snooper):
 
         # Write the header
         self.output.write(
-            self.IDENTIFICATION_PATTERN + struct.pack('>LL', 1, self.DataLinkType.H4)
+            self.IDENTIFICATION_PATTERN + struct.pack(">LL", 1, self.DataLinkType.H4)
         )
 
     def snoop(self, hci_packet: bytes, direction: Snooper.Direction) -> None:
@@ -85,14 +85,20 @@ class BtSnooper(Snooper):
 
         # Compute the current timestamp
         timestamp = (
-            int((datetime.datetime.utcnow() - self.TIMESTAMP_ANCHOR) / self.ONE_MS)
+            int(
+                (
+                    datetime.datetime.now(tz=datetime.timezone.utc)
+                    - self.TIMESTAMP_ANCHOR
+                )
+                / self.ONE_MS
+            )
             + self.TIMESTAMP_DELTA
         )
 
         # Emit the record
         self.output.write(
             struct.pack(
-                '>IIIIQ',
+                ">IIIIQ",
                 len(hci_packet),  # Original Length
                 len(hci_packet),  # Included Length
                 flags,  # Packet Flags
@@ -129,7 +135,7 @@ def create_snooper(spec: str) -> Generator[Snooper, None, None]:
           records will be written to that file if it can be opened/created.
           The keyword args that may be referenced by the string pattern are:
             now: the value of `datetime.now()`
-            utcnow: the value of `datetime.utcnow()`
+            utcnow: the value of `datetime.datetime(tz=datetime.timezone.utc)`
             pid: the current process ID.
             instance: the instance ID in the current process.
 
@@ -138,34 +144,34 @@ def create_snooper(spec: str) -> Generator[Snooper, None, None]:
       btsnoop:file:/tmp/bumble_{now:%Y-%m-%d-%H:%M:%S}_{pid}.log
 
     """
-    if ':' not in spec:
-        raise core.InvalidArgumentError('snooper type prefix missing')
+    if ":" not in spec:
+        raise core.InvalidArgumentError("snooper type prefix missing")
 
-    snooper_type, snooper_args = spec.split(':', maxsplit=1)
+    snooper_type, snooper_args = spec.split(":", maxsplit=1)
 
-    if snooper_type == 'btsnoop':
-        if ':' not in snooper_args:
-            raise core.InvalidArgumentError('I/O type for btsnoop snooper type missing')
+    if snooper_type == "btsnoop":
+        if ":" not in snooper_args:
+            raise core.InvalidArgumentError("I/O type for btsnoop snooper type missing")
 
-        io_type, io_name = snooper_args.split(':', maxsplit=1)
-        if io_type == 'file':
+        io_type, io_name = snooper_args.split(":", maxsplit=1)
+        if io_type == "file":
             # Process the file name string pattern.
             global _SNOOPER_INSTANCE_COUNT
             file_path = io_name.format(
                 now=datetime.datetime.now(),
-                utcnow=datetime.datetime.utcnow(),
+                utcnow=datetime.datetime.now(tz=datetime.timezone.utc),
                 pid=os.getpid(),
                 instance=_SNOOPER_INSTANCE_COUNT,
             )
 
             # Open the file
-            logger.debug(f'Snoop file: {file_path}')
-            with open(file_path, 'wb') as snoop_file:
+            logger.debug(f"Snoop file: {file_path}")
+            with open(file_path, "wb") as snoop_file:
                 _SNOOPER_INSTANCE_COUNT += 1
                 yield BtSnooper(snoop_file)
                 _SNOOPER_INSTANCE_COUNT -= 1
                 return
 
-        raise core.InvalidArgumentError(f'I/O type {io_type} not supported')
+        raise core.InvalidArgumentError(f"I/O type {io_type} not supported")
 
-    raise core.InvalidArgumentError(f'snooper type {snooper_type} not found')
+    raise core.InvalidArgumentError(f"snooper type {snooper_type} not found")