diff --git a/stdlib/3/base64.pyi b/stdlib/3/base64.pyi
index 387e11f57..4e76ebbd9 100644
--- a/stdlib/3/base64.pyi
+++ b/stdlib/3/base64.pyi
@@ -1,21 +1,38 @@
 # Stubs for base64
 
-# Based on http://docs.python.org/3.2/library/base64.html
-
 from typing import IO, Union
+import sys
 
-def b64encode(s: bytes, altchars: bytes = ...) -> bytes: ...
-def b64decode(s: Union[bytes, str], altchars: bytes = ...,
+
+if sys.version_info <= (3, 2):
+    _encodable = bytes
+    _decodable = bytes
+elif sys.version_info[:2] == (3, 3):
+    _encodable = bytes
+    _decodable = Union[bytes, str]
+elif sys.version_info >= (3, 4):
+    _encodable = Union[bytes, bytearray, memoryview]
+    _decodable = Union[bytes, bytearray, memoryview, str]
+
+def b64encode(s: _encodable, altchars: bytes = ...) -> bytes: ...
+def b64decode(s: _decodable, altchars: bytes = ...,
               validate: bool = ...) -> bytes: ...
-def standard_b64encode(s: bytes) -> bytes: ...
-def standard_b64decode(s: bytes) -> bytes: ...
-def urlsafe_b64encode(s: bytes) -> bytes: ...
-def urlsafe_b64decode(s: bytes) -> bytes: ...
-def b32encode(s: bytes) -> bytes: ...
-def b32decode(s: bytes, casefold: bool = ...,
+def standard_b64encode(s: _encodable) -> bytes: ...
+def standard_b64decode(s: _decodable) -> bytes: ...
+def urlsafe_b64encode(s: _encodable) -> bytes: ...
+def urlsafe_b64decode(s: _decodable) -> bytes: ...
+def b32encode(s: _encodable) -> bytes: ...
+def b32decode(s: _decodable, casefold: bool = ...,
               map01: bytes = ...) -> bytes: ...
-def b16encode(s: bytes) -> bytes: ...
-def b16decode(s: bytes, casefold: bool = ...) -> bytes: ...
+def b16encode(s: _encodable) -> bytes: ...
+def b16decode(s: _decodable, casefold: bool = ...) -> bytes: ...
+if sys.version_info >= (3, 4):
+    def a85encode(b: _encodable, *, foldspaces: bool = ..., wrapcol: int = ...,
+                  pad: bool = ..., adobe: bool = ...) -> bytes: ...
+    def a85decode(b: _decodable, *, foldspaces: bool = ...,
+                  adobe: bool = ..., ignorechars: Union[str, bytes] = ...) -> bytes: ...
+    def b85encode(b: _encodable, pad: bool = ...) -> bytes: ...
+    def b85decode(b: _decodable) -> bytes: ...
 
 def decode(input: IO[bytes], output: IO[bytes]) -> None: ...
 def decodebytes(s: bytes) -> bytes: ...