This is a non trivial operation. Only proceed if you have adequate rollback mechanisms in place, such as snapshots of your virtual machines and a backup of the database.

ALL INSTALLATIONS

• MAKE SURE THE JTEL PORTAL IS AT LEAST 5.15 BEFORE STARTING.
• MAKE SURE THE OPERATING SYSTEM IS UP TO DATE

INSTALLATIONS WITH REPLICATION

• MAKE SURE THAT REPLICATION IS WORKING CORRECTLY BEFORE STARTING.
• ALWAYS UPDATE SLAVES COMPLETELY TO 8.x FIRST - BEFORE UPDATING THE MASTERCOMPLETE PHASE 1 FIRST FOR ALL SERVERS, STARTING WITH THE SLAVES.
• WHEN UPDATING MASTER-MASTER CONFIGURATIONS, STOP THE OTHER MASTER BEFORE STARTING THE UPDATE PROCESS with service mysqld stop.
• MAKE SURE THAT BOTH MASTERS ARE 8.x BEFORE RESTARTING BOTH AT THE SAME TIME.