If you are upgrading both the Controller and agents, first upgrade the Controller and then upgrade the agents.
Also, if you are upgrading multiple agents in your monitored environment, upgrade the agents for the tiers on which business transactions originate last. For more information about this requirement, along with Controller and agent compatibility information, see Agent and Controller Compatibility.
Upgrade the PHP Agent
1. Shut down the web server or php-fpm.
2. Copy the controller host, controller port, application name, tier name and node name property values from your ini file.
If you are running in multi-tenant mode, also copy the account name and account access key property values.
3. Recursively remove or rename the old AppDynamics PHP installation directory.
4. Download and extract the most recent agent tarball.
5. Run the installation script.
Beginning in 4.1, you must pass the controller access key as one of the options to the installer.
To find your access key, click the Settings > License > Account.
6. Restart Apache or php-fpm.
If you are using the agent to monitor PHP CLI without running a web server, you can omit steps 1 and 6.