Could you please share below points ,
1. I know with jboss-cli.sh "patch info" but how many ways veify for patch successully applied or not .
2. what is the prerequistes for jboss patch upgrade
3. from jboss 6.4.8 to jboss 6.4.20 require actions (pre and post activity )
4. what are the challenges while apply patch time , kindly provide manual steps with commands
5. how to avoid jboss patch failure
I see a migration guide that has discussed the migration in detail. It is available at the below link
I hope this guide has answers to your questions.