Updating Limesurvey can be tricky if you do it manually. When updating from a pretty old Limesurvey version to the latest releases and your system contains lots of survey, then there is a high risk that updating the database during the Limesurvey update can fail due to a time out or limited resources. This can cause the update to fail before finishing the update process and lead to your whole Limesurvey system being down.
We have updated dozens of Limesurvey systems and are familiar with all potential issues. So if you need some expert help for updating your Limesurvey system just drop us a note.