Upgrade SEPM 12.1.5 to 12.1.6 MP4

Hello,

I have two SEPM's connected to a SQL server DB. The version is 12.1.5 and I want to migrate to 12.1.6 MP4(last version).

How can I do the Upgrade?  I `ve found information about the upgrade process, however it doesn't have the details. 

Can you give me information with a step to step about the upgrate in each SEPM(tutorial), since the version is 12.1.5 to 12.1.6 MP4.  

Also I have extra questions about  the process: 

- Which SEPM I should upgrade first?

- Details about the process to back up and prepare for disaster recovery.

- Detail about how to stop the replication SEPM?

A video where show the upgrade process will be very useful for SEPM admins.

Thanks you for your help.

Regards.