diff --git a/Doc/lib/libunittest.tex b/Doc/lib/libunittest.tex
index 980d706..1cd2857 100644
--- a/Doc/lib/libunittest.tex
+++ b/Doc/lib/libunittest.tex
@@ -7,6 +7,7 @@
 \sectionauthor{Steve Purcell}{stephen\textunderscore{}purcell@yahoo.com}
 \sectionauthor{Fred L. Drake, Jr.}{fdrake@acm.org}
 
+\versionadded{2.1}
 
 The Python unit testing framework, often referred to as ``PyUnit,'' is
 a Python language version of JUnit, by Kent Beck and Erich Gamma.