diff --git a/stubs/simplejson/@tests/stubtest_allowlist.txt b/stubs/simplejson/@tests/stubtest_allowlist.txt
index 84e705994309..ebb5d87976c4 100644
--- a/stubs/simplejson/@tests/stubtest_allowlist.txt
+++ b/stubs/simplejson/@tests/stubtest_allowlist.txt
@@ -2,6 +2,8 @@
 simplejson.scanner.make_scanner
 simplejson.scanner.JSONDecodeError.__init__
 simplejson.encoder.c_make_encoder
+simplejson.encoder.c_encode_basestring
+simplejson.encoder.py_encode_basestring
 simplejson.encoder.c_encode_basestring_ascii
 simplejson.encoder.py_encode_basestring_ascii
 
diff --git a/stubs/simplejson/METADATA.toml b/stubs/simplejson/METADATA.toml
index 63c9ff16b4b7..d88621057572 100644
--- a/stubs/simplejson/METADATA.toml
+++ b/stubs/simplejson/METADATA.toml
@@ -1,2 +1,2 @@
-version = "3.20.*"
+version = "4.1.*"
 upstream-repository = "https://github.com/simplejson/simplejson"
diff --git a/stubs/simplejson/simplejson/__init__.pyi b/stubs/simplejson/simplejson/__init__.pyi
index 73dd284fbe41..b89f04f64fdf 100644
--- a/stubs/simplejson/simplejson/__init__.pyi
+++ b/stubs/simplejson/simplejson/__init__.pyi
@@ -124,6 +124,7 @@ def loads(
     object_pairs_hook: Callable[[list[tuple[Any, Any]]], Any] | None = None,
     use_decimal: bool = False,
     allow_nan: bool = False,
+    array_hook: Callable[[list[Any]], Any] | None = None,  # transforms a JSON value to an arbitrary value
     **kw: Any,
 ) -> Any: ...
 @overload
@@ -138,6 +139,7 @@ def loads(
     object_pairs_hook: Callable[[list[tuple[Any, Any]]], Any] | None = None,
     use_decimal: bool = False,
     allow_nan: bool = False,
+    array_hook: Callable[[list[Any]], Any] | None = None,  # transforms a JSON value to an arbitrary value
 ) -> Any: ...
 
 @overload
@@ -153,6 +155,7 @@ def load(
     object_pairs_hook: Callable[[list[tuple[Any, Any]]], Any] | None = None,
     use_decimal: bool = False,
     allow_nan: bool = False,
+    array_hook: Callable[[list[Any]], Any] | None = None,  # transforms a JSON value to an arbitrary value
     **kw: Any,
 ) -> Any: ...
 @overload
@@ -167,6 +170,7 @@ def load(
     object_pairs_hook: Callable[[list[tuple[Any, Any]]], Any] | None = None,
     use_decimal: bool = False,
     allow_nan: bool = False,
+    array_hook: Callable[[list[Any]], Any] | None = None,  # transforms a JSON value to an arbitrary value
 ) -> Any: ...
 
 def simple_first(kv: tuple[_T, object]) -> tuple[bool, _T]: ...
diff --git a/stubs/simplejson/simplejson/decoder.pyi b/stubs/simplejson/simplejson/decoder.pyi
index 4afa6ea9360c..3fc18bc176e5 100644
--- a/stubs/simplejson/simplejson/decoder.pyi
+++ b/stubs/simplejson/simplejson/decoder.pyi
@@ -1,3 +1,4 @@
+from _typeshed import Incomplete
 from collections.abc import Callable
 from re import Match
 from typing import Any, Literal
@@ -5,11 +6,17 @@ from typing import Any, Literal
 class JSONDecoder:
     encoding: str
     object_hook: Callable[[dict[Any, Any]], Any] | None
+    # transforms a list of (key, json_value) pairs to an arbitrary value
+    object_pairs_hook: Callable[[list[tuple[str, Any]]], Any] | None
     parse_float: Callable[[str], Any] | None
     parse_int: Callable[[str], Any] | None
     parse_constant: Callable[[str], Any] | None
     strict: bool
-    object_pairs_hook: Callable[[list[tuple[Any, Any]]], Any] | None
+    array_hook: Callable[[list[Any]], Any] | None  # transforms a JSON value to an arbitrary value
+    # They have many parameters, it might be better to use Protocol:
+    parse_object: Callable[..., tuple[Incomplete, int]]
+    parse_array: Callable[..., tuple[Incomplete, int]]
+    parse_string: Callable[..., tuple[Incomplete, int]]
     memo: dict[Any, Any]
     scan_once: Callable[[str, int], tuple[bool, int]]
 
@@ -23,6 +30,7 @@ class JSONDecoder:
         strict: bool = True,
         object_pairs_hook: Callable[[list[tuple[Any, Any]]], Any] | None = None,
         allow_nan: bool = False,
+        array_hook: Callable[[list[Any]], Any] | None = None,  # transforms a JSON value to an arbitrary value
     ) -> None: ...
     def decode(self, s: str, _w: Callable[[str, int], Match[str]] = ..., _PY3: Literal[True] = True) -> Any: ...
     def raw_decode(
diff --git a/stubs/simplejson/simplejson/encoder.pyi b/stubs/simplejson/simplejson/encoder.pyi
index 15378765980d..eebf18a2503e 100644
--- a/stubs/simplejson/simplejson/encoder.pyi
+++ b/stubs/simplejson/simplejson/encoder.pyi
@@ -1,7 +1,7 @@
 import re
 from _typeshed import SupportsRichComparison
 from collections.abc import Callable, Iterator
-from typing import Any, Literal, NoReturn
+from typing import Any, NoReturn
 
 ESCAPE: re.Pattern[str]
 ESCAPE_ASCII: re.Pattern[str]
@@ -56,5 +56,5 @@ class JSONEncoder:
 
 class JSONEncoderForHTML(JSONEncoder): ...
 
-def encode_basestring(s: str | bytes, _PY3: Literal[True] = True, _q: str = '"') -> str: ...
+def encode_basestring(s: str | bytes, /) -> str: ...
 def encode_basestring_ascii(s: str | bytes, /) -> str: ...