diff --git a/stdlib/3/os/__init__.pyi b/stdlib/3/os/__init__.pyi
index de5a34a63..165eac918 100644
--- a/stdlib/3/os/__init__.pyi
+++ b/stdlib/3/os/__init__.pyi
@@ -322,7 +322,12 @@ def close(fd: int) -> None: ...
 def closerange(fd_low: int, fd_high: int) -> None: ...
 def device_encoding(fd: int) -> Optional[str]: ...
 def dup(fd: int) -> int: ...
-def dup2(fd: int, fd2: int) -> None: ...
+if sys.version_info >= (3, 7):
+    def dup2(fd: int, fd2: int, inheritable: bool = ...) -> int: ...
+elif sys.version_info >= (3, 4):
+    def dup2(fd: int, fd2: int, inheritable: bool = ...) -> None: ...
+else:
+    def dup2(fd: int, fd2: int) -> None: ...
 def fstat(fd: int) -> stat_result: ...
 def fsync(fd: int) -> None: ...
 def lseek(fd: int, pos: int, how: int) -> int: ...