diff --git a/install b/install
index 1a2dd14..25daafd 100755
--- a/install
+++ b/install
@@ -33,7 +33,9 @@ shopt -s nocasematch
 # Global configuration  
 ISABELLE_VERSION="Isabelle2018: August 2018"
 ISABELLE_URL="https://isabelle.in.tum.de/website-Isabelle2018/"
-AFP_URL="https://sourceforge.net/projects/afp/files/afp-Isabelle2018/afp-2019-06-04.tar.gz"
+
+AFP_DATE="afp-2019-06-04"
+AFP_URL="https://sourceforge.net/projects/afp/files/afp-Isabelle2018/"$AFP_DATE".tar.gz"
 
 print_help()
 {
@@ -100,14 +102,14 @@ check_afp_entries() {
         echo "           Trying to install AFP (this might take a few *minutes*) ...."
 	extract=""
 	for e in $missing; do
-	    extract="$extract afp-2019-06-04/thys/$e"
+	    extract="$extract $AFP_DATE/thys/$e"
 	done
 	mkdir -p .afp
         if curl -s -L $AFP_URL | tar zxf - -C .afp $extract; then 
             for e in $missing; do 
                 echo "           Registering $e in $ISABELLE_HOME_USER/ROOTS"
 		touch $ISABELLE_HOME_USER/ROOTS
-		grep -q $PWD/.afp/afp-2018-08-14/thys/$e $ISABELLE_HOME_USER/ROOTS || echo "$PWD/.afp/afp-2018-08-14/thys/$e" >> $ISABELLE_HOME_USER/ROOTS 
+		grep -q $PWD/.afp/$AFP_DATE/thys/$e $ISABELLE_HOME_USER/ROOTS || echo "$PWD/.afp/$AFP_DATE/thys/$e" >> $ISABELLE_HOME_USER/ROOTS 
             done
             echo "           AFP installation successful."
         else