diff --git a/bson/__init__.py b/bson/__init__.py
index 8f8d58562..972b18401 100644
--- a/bson/__init__.py
+++ b/bson/__init__.py
@@ -663,9 +663,8 @@ def _make_c_string(string: Union[str, bytes]) -> bytes:
 
 def _make_name(string: str) -> bytes:
     """Make a 'C' string suitable for a BSON key."""
-    # Keys can only be text in python 3.
     if "\x00" in string:
-        raise InvalidDocument("BSON keys / regex patterns must not contain a NUL character")
+        raise InvalidDocument("BSON keys must not contain a NUL character")
     return _utf_8_encode(string)[0] + b"\x00"
 
 
diff --git a/bson/_cbsonmodule.c b/bson/_cbsonmodule.c
index 9fcb1b9e3..3fce1f9d7 100644
--- a/bson/_cbsonmodule.c
+++ b/bson/_cbsonmodule.c
@@ -3211,7 +3211,6 @@ PyInit__cbson(void)
         (void *) buffer_write_int32_at_position;
     _cbson_API[_cbson_downcast_and_check_INDEX] = (void *) _downcast_and_check;
 
-    /* PyCapsule is new in python 3.1 */
     c_api_object = PyCapsule_New((void *) _cbson_API, "_cbson._C_API", NULL);
     if (c_api_object == NULL)
         INITERROR;
diff --git a/bson/binary.py b/bson/binary.py
index 77e3a3d47..9a0c06138 100644
--- a/bson/binary.py
+++ b/bson/binary.py
@@ -197,12 +197,11 @@ class Binary(bytes):
     what should be considered a string when we encode to BSON.
 
     Raises TypeError if `data` is not an instance of :class:`bytes`
-    (:class:`str` in python 2) or `subtype` is not an instance of
-    :class:`int`. Raises ValueError if `subtype` is not in [0, 256).
+    or `subtype` is not an instance of :class:`int`.
+    Raises ValueError if `subtype` is not in [0, 256).
 
     .. note::
-      In python 3 instances of Binary with subtype 0 will be decoded
-      directly to :class:`bytes`.
+      Instances of Binary with subtype 0 will be decoded directly to :class:`bytes`.
 
     :Parameters:
       - `data`: the binary data to represent. Can be any bytes-like type
diff --git a/pymongo/auth.py b/pymongo/auth.py
index b4d04f8d1..b41e88542 100644
--- a/pymongo/auth.py
+++ b/pymongo/auth.py
@@ -189,7 +189,7 @@ def _build_credentials_tuple(
 
 
 def _xor(fir: bytes, sec: bytes) -> bytes:
-    """XOR two byte strings together (python 3.x)."""
+    """XOR two byte strings together."""
     return b"".join([bytes([x ^ y]) for x, y in zip(fir, sec)])
 
 
diff --git a/pymongo/mongo_client.py b/pymongo/mongo_client.py
index 96b5a5158..c8a265622 100644
--- a/pymongo/mongo_client.py
+++ b/pymongo/mongo_client.py
@@ -518,12 +518,11 @@ class MongoClient(common.BaseObject, Generic[_DocumentType]):
           - `tlsCertificateKeyFile`: A file containing the client certificate
             and private key. Implies ``tls=True``. Defaults to ``None``.
           - `tlsCRLFile`: A file containing a PEM or DER formatted
-            certificate revocation list. Only supported by python 2.7.9+
-            (pypy 2.5.1+). Implies ``tls=True``. Defaults to ``None``.
+            certificate revocation list. Implies ``tls=True``. Defaults to
+            ``None``.
           - `tlsCertificateKeyFilePassword`: The password or passphrase for
             decrypting the private key in ``tlsCertificateKeyFile``. Only
-            necessary if the private key is encrypted. Only supported by
-            python 2.7.9+ (pypy 2.5.1+) and 3.3+. Defaults to ``None``.
+            necessary if the private key is encrypted. Defaults to ``None``.
           - `tlsDisableOCSPEndpointCheck`: (boolean) If ``True``, disables
             certificate revocation status checking via the OCSP responder
             specified on the server certificate.
diff --git a/test/test_bson.py b/test/test_bson.py
index 12fbea92f..bde0e0815 100644
--- a/test/test_bson.py
+++ b/test/test_bson.py
@@ -529,8 +529,8 @@ class TestBSON(unittest.TestCase):
     def test_bytes_as_keys(self):
         doc = {b"foo": "bar"}
         # Since `bytes` are stored as Binary you can't use them
-        # as keys in python 3.x. Using binary data as a key makes
-        # no sense in BSON anyway and little sense in python.
+        # as keys. Using binary data as a key makes no sense in BSON
+        # anyway and little sense in python.
         self.assertRaises(InvalidDocument, encode, doc)
 
     def test_datetime_encode_decode(self):