In Aperture, instead of manually switching on and then off again Agent Upgraders, setup an Agent group to do this for you automatically.
Create a new Agent Group
1. In the nav bar, choose 'Agents' > 'Groups'
2. Click the button to '+ Add a Group'
3. Name the group, and leave Agent Type set to default 'Agent Installed'
4. Click '+ Add a Group'
Set Membership Criteria
1. Choose the option 'Membership Criteria'
Here, you'll set two criteria, one for the type and another for the version. It should look like the following, (where the version number is set to the current agent version that should be upgraded to the latest, in the example below the version is 14.3)
Turn On the upgrader
1. Choose 'Work' > 'Agent Upgrade'
2. Select 'Yes' under 'Upgrade agents to latest version?
3. Choose 'Save'
Now, each agent with the matching version will update once and then no longer qualify for this group (because they are now on a different version).