Case update email

Need Suitecrm to send email notification to customer when his/her case is updated. Do I need one workflow condition/action per customer case or I can use single workflow?

Figured out how to set a workflow to send case update emails. Two issues remains, may be only in 7.10, 1. sometimes it works, but other times either an old update gets sent in the email or just the $variables. The other issue is it uses default email from address, there is no way to tell it to use specific email address even you can create more than one email for outbound emails.

Example email body with $variables instead of content of the variables:
Most Recent Case Update:
Entered on $aop_case_updates_date_modified