If you downloaded a new release from our project page you can install a new version depending on the type of the release.
If the release has some changes in the general database structure you need to install the new database also (see at the database sections how).
A new web application can be installed as described at the application servers (in this guideline Tomcat). If no database changes are necessary you can
run multiple versions of our software if required.
We intend to avoid the changes in the general database structure as much as possible, but we can't avoid them.
If you have valuable data that you want to keep you can export and import the data in the database coming with the new release.