First of all; take a backup copy of your current installation, including the database!
Shut down your Tomcat server
Again, make sure that you have made a backup of your Tomcat webapp (all files) and the database!
Go to the directory 'WEB-INF/lib' and remove all the files.
Extract the content from 'vp_installed_v7.1_upgrade_from_v7.0.2-20110411.zip' over your current installation.
Update your VisionProject database by running the SQL script 'upgrade_from_v7.0.2_to_v7.1.sql' located in the directory: '/WEB-INF/internal_docs/installed version/db_scripts/v7.1/Upgrade from v7.0.2'. Choose the directory that match your database, MS SQL Server or MySQL.
You are done and can start Tomcat again!
NOTE! We have upgraded EhCache in this version and because of that you might encounter an error like "Error: java.io.InvalidClassException: net.sf.ehcache.Element; local class incompatible: stream ..." when trying to login. To solve this issue you have to shutdown Tomcat, remove all *.data and *.index files in /temp and then startup Tomcat again.