InterpolationSyntaxError was added in 2.3
diff --git a/Doc/lib/libcfgparser.tex b/Doc/lib/libcfgparser.tex
index 92e3f9c..9951645 100644
--- a/Doc/lib/libcfgparser.tex
+++ b/Doc/lib/libcfgparser.tex
@@ -101,6 +101,7 @@
 \begin{excdesc}{InterpolationSyntaxError}
 Exception raised when the source text into which substitutions are
 made does not conform to the required syntax.
+\versionadded{2.3}
 \end{excdesc}
 
 \begin{excdesc}{MissingSectionHeaderError}