diff --git a/stdlib/2and3/base64.pyi b/stdlib/2and3/base64.pyi
index 03dd593bd..2385f4071 100644
--- a/stdlib/2and3/base64.pyi
+++ b/stdlib/2and3/base64.pyi
@@ -32,7 +32,8 @@ if sys.version_info >= (3, 4):
 
 def decode(input: IO[bytes], output: IO[bytes]) -> None: ...
 def decodebytes(s: bytes) -> bytes: ...
-def decodestring(s: bytes) -> bytes: ...
 def encode(input: IO[bytes], output: IO[bytes]) -> None: ...
 def encodebytes(s: bytes) -> bytes: ...
-def encodestring(s: bytes) -> bytes: ...
+if sys.version_info < (3, 9):
+    def encodestring(s: bytes) -> bytes: ...
+    def decodestring(s: bytes) -> bytes: ...