--- a/src/Doc/Prog_Prove/document/intro-isabelle.tex Mon Nov 18 10:34:21 2019 +0100
+++ b/src/Doc/Prog_Prove/document/intro-isabelle.tex Mon Nov 18 15:00:48 2019 +0100
@@ -55,7 +55,7 @@
\subsection*{Getting Started with Isabelle}
If you have not done so already, download and install Isabelle
-(this book is compatible with Isabelle2018)
+(this book is compatible with Isabelle2020)
from \url{https://isabelle.in.tum.de}. You can start it by clicking
on the application icon. This will launch Isabelle's
user interface based on the text editor \concept{jEdit}. Below you see