For reasons of operational safety, all IT technical systems of the HRZ are subject to maintenance. A distinction must be made between regular maintenance and security-critical updates:

• Regular maintenance: These are updates to be installed on a regular basis that fix bugs and possibly extend the range of functions.
• *Security-critical updates**: These are updates that must be installed immediately, as without them the security of the IT technical system cannot be guaranteed.

Security-critical updates must therefore always be installed immediately. Since not all systems are available in a clustered, fail-safe form, this necessarily leads to interruptions in operation, even during the semester, which unfortunately cannot be avoided.

Regular maintenance is installed at fixed times. Here, too, not all systems are available in a clustered, fail-safe form, and this also leads to interruptions in operation.

• Regular maintenance is carried out during the lecture-free period if possible, i.e. preferably in the months of February and August.
• Work is announced 7-14 days in advance by e-mail to the affected groups of people.
• The work usually takes place on weekdays between 08-18 hrs.
• At the beginning of the announced date, the maintenance work is displayed in InfoSys.