add versionadded
diff --git a/Doc/library/warnings.rst b/Doc/library/warnings.rst
index 091327f..d36955f 100644
--- a/Doc/library/warnings.rst
+++ b/Doc/library/warnings.rst
@@ -279,6 +279,8 @@
    be a string and *category* a subclass of :exc:`Warning`. :func:`warnpy3k`
    is using :exc:`DeprecationWarning` as default warning class.
 
+   .. versionadded:: 2.6
+
 
 .. function:: showwarning(message, category, filename, lineno[, file[, line]])