Update abstract.tex

Revert to 3.4 in one more place.

Author: HansOlsson

chapters/abstract.tex

@@ -9,7 +9,7 @@
 \includegraphics[width=10cm]{image1}
 \end{center}
 This document defines the Modelica\footnote{Modelica is a registered
-  trademark of the Modelica Association} language, version 3.5, which is
+  trademark of the Modelica Association} language, version 3.4, which is
 developed by the Modelica Association, a non-profit organization with
 seat in Linköping, Sweden. Modelica is a freely available,
 object-oriented language for modeling of large, complex, and