It depends on the corporate decision. The system forwarded typically includes an update manager that can be used either by us or the Client to initiate an update. The update package in this has been tested. In the case of complex, individual business systems, updates can be released on a daily basis and are usually updated at a pre-arranged time.
Most of the time we trigger the update package in the end of the automated work process, so it can be tested immediately in the live environment. If there is a bug in the code, there is still time to either revert to the previous version or fix the problem parts quickly.