added a few missing \versionadded{2.3} tags
diff --git a/Doc/lib/libpickletools.tex b/Doc/lib/libpickletools.tex
index 0fe76ff..8f63626 100644
--- a/Doc/lib/libpickletools.tex
+++ b/Doc/lib/libpickletools.tex
@@ -3,6 +3,8 @@
\declaremodule{standard}{pickletools}
\modulesynopsis{Contains extensive comments about the pickle protocols and pickle-machine opcodes, as well as some useful functions.}
+\versionadded{2.3}
+
This module contains various constants relating to the intimate
details of the \refmodule{pickle} module, some lengthy comments about
the implementation, and a few useful functions for analyzing pickled