add os version check

update

@@ -45,6 +45,48 @@ FINISH() {
 
 trap FINISH EXIT
 
+#####################################
+#	Old OS Check
+#####################################
+V_ID=$(grep VERSION_ID /etc/os-release | sed 's/VERSION_ID="//;s/"//')
+
+if [ "$V_ID" -le 10 ]; then
+NOTICEPATH=/run/user/$UID
+
+cat <<EOF >${NOTICEPATH}/intro.txt
+Build a Pi 3.2.0 and later does not support
+RaspiOS Buster or earlier versions of RaspiOS.
+You should consider upgrading to RaspiOS 11
+(Bullseye). By clicking ok you will be moved
+to the last version of Build a Pi (3.1.4) that 
+supports Pi OS Buster. Please note there are 
+no plans to update Build a Pi for Buster going 
+forward.  In other words, you are on your own 
+if it is broke and you are still running Pi OS
+10 (Buster).
+
+EOF
+
+INTRO=$(yad --width=600 --height=300 --text-align=center --center --title="Out of Date OS Detected!" --show-uri \
+	--image ${LOGO} --window-icon=${LOGO} --image-on-top --separator="|" --item-separator="|" \
+	--text-info \
+	--button="OK":1 <${NOTICEPATH}/intro.txt \
+	--button="Exit":2 \
+	>/dev/null 2>&1)
+	BUT=$?
+	echo $BUT
+	if [ $BUT = 2 ] || [ $BUT = 252 ]; then
+	exit
+	fi
+	rm ${NOTICEPATH}/intro.txt
+	cd $HOME/pi-build
+	git checkout buster 
+	bash build-a-pi & exit
+
+#####################################
+#	end Old OS Check
+#####################################
+
 #remove temp dir if exist
 #fix issue 108 https://github.com/km4ack/pi-build/issues/108
 #Thanks to N5RKS for finding the bug