Hmm... better add a version annotation for the Iterator Protocol section.

Doc/api/api.tex

@@ -2092,6 +2092,8 @@ statement \samp{\var{o}[\var{key}] = \var{v}}.
 
 \section{Iterator Protocol \label{iterator}}
 
+\versionadded{2.2}
+
 There are only a couple of functions specifically for working with
 iterators.