diff --git a/sphinx/application.py b/sphinx/application.py
index 99f2b81bd8b..58e61f7ec39 100644
--- a/sphinx/application.py
+++ b/sphinx/application.py
@@ -1119,8 +1119,9 @@ def add_lexer(self, alias: str, lexer: type[Lexer]) -> None:
 
         .. versionadded:: 0.6
         .. versionchanged:: 2.1
-           Take a lexer class as an argument.  An instance of lexers are
-           still supported until Sphinx-3.x.
+           Take a lexer class as an argument.
+        .. versionchanged:: 4.0
+           Removed support for lexer instances as an argument.
         """
         logger.debug('[app] adding lexer: %r', (alias, lexer))
         lexer_classes[alias] = lexer
diff --git a/sphinx/domains/python.py b/sphinx/domains/python.py
index 2fdd79e866e..c461cc311fd 100644
--- a/sphinx/domains/python.py
+++ b/sphinx/domains/python.py
@@ -1368,7 +1368,7 @@ def resolve_xref(self, env: BuildEnvironment, fromdocname: str, builder: Builder
                                 type, searchmode)
 
         if not matches and type == 'attr':
-            # fallback to meth (for property; Sphinx-2.4.x)
+            # fallback to meth (for property; Sphinx 2.4.x)
             # this ensures that `:attr:` role continues to refer to the old property entry
             # that defined by ``method`` directive in old reST files.
             matches = self.find_obj(env, modname, clsname, target, 'meth', searchmode)
diff --git a/sphinx/ext/intersphinx.py b/sphinx/ext/intersphinx.py
index c07ffc145be..2486d29d169 100644
--- a/sphinx/ext/intersphinx.py
+++ b/sphinx/ext/intersphinx.py
@@ -360,10 +360,10 @@ def _resolve_reference_in_domain(env: BuildEnvironment,
                                  ) -> nodes.reference | None:
     # we adjust the object types for backwards compatibility
     if domain.name == 'std' and 'cmdoption' in objtypes:
-        # until Sphinx-1.6, cmdoptions are stored as std:option
+        # cmdoptions were stored as std:option until Sphinx 1.6
         objtypes.append('option')
     if domain.name == 'py' and 'attribute' in objtypes:
-        # Since Sphinx-2.1, properties are stored as py:method
+        # properties are stored as py:method since Sphinx 2.1
         objtypes.append('method')
 
     # the inventory contains domain:type as objtype