Closes #10142: Support for SEEK_HOLE/SEEK_DATA
diff --git a/Doc/library/io.rst b/Doc/library/io.rst
index e30a016..1d3d702 100644
--- a/Doc/library/io.rst
+++ b/Doc/library/io.rst
@@ -291,6 +291,11 @@
.. versionadded:: 3.1
The ``SEEK_*`` constants.
+ .. versionadded:: 3.3
+ Some operating systems could support additional values, like
+ :data:`os.SEEK_HOLE` or :data:`os.SEEK_DATA`. The valid values
+ for a file could depend on it being open in text or binary mode.
+
.. method:: seekable()
Return ``True`` if the stream supports random access. If ``False``,