We need to upgrade an HA pair SBC from version 7.2.2.0 to 7.2.2.2 and apply a hotfix to correct the Blacklist feature that is not working. Avaya documentation states to upgrade the EMS server first, then the HA pairs and repeat the process for the hotfix. My questions are as follows: (1) how long should it take to complete the upgrade and apply the hotfix; (2) since we have an HA pair configuration will there be down time for our SIP trunking?