First of all; take a backup copy of your current installation!
Both the directory in the Tomcat webapp and the database!
Unzip the vp_installed_2_4_upgrade_from_2_3.zip anywhere on your disk
Start to update your VisionFlow database by running the SQL scripts included in the directory: '\WEB-INF\internal_docs\installed version\db_scripts\v2.4\Upgrade_from_2_3', from 01.Query.sql to 14. Query_and_IssueField_Update.sql.
Take a copy of the file web-inf\struts-config.xml.
Then you can copy your unzipped files from 1. into your VisionFlow webapp.
A new struts-config.xml has now been copied into your VisionFlow installation and you now need to change the database properties to the ones you had originally.
[Optional] Insert the line:
sendNotificationsToCustomers = false
sendNotificationsToCustomers = true
into the VisionFlow.properties (web-inf\classes). true means that Notifications will be sent to users with the role Customer if the Notification is setup to do so and the user have the Enable E-mail Notification flag checked. The default value is false.
[Optional] If you have enabled the branding option (in the Additional Features) you have to update your branding stylesheet file. Please see the following article for instructions.