This article explains the available options under "Application Visibility" and their respective use.

On MIST UI under "Application Visibility", we see three options:

1. Device HAS an APP Track license
2. Device does Not have an APP Track license
3. Use site setting for APP Track license

As mentioned on the MIST UI, "App Track license is used to collect data for monitoring applications and service levels"

On MIST UI under "Application Visibility", we see three options:

1. Device HAS an APP Track license
   1. Upon selecting this option, MIST pushes the required Application Database to the WAN Edge (SRX), and it will get installed.
2. Device does Not have an APP Track license
   1. Upon selecting this option, MIST will not push the Application Database.
3. Use site setting for APP Track license
   1. Based on the setting for the site under "Organisation -> Site Settings -> Choose the site name -> Under "WAN Edge Advanced Security"
      1. If you check "My SRX devices have an App Track license", the behaviour will be the same as Option #1
      2. If you leave "My SRX devices have an App Track license" unchecked, the behaviour will be the same as Option #2

Please note that if you have the following configuration, it is MANDATORY to choose this as "Device HAS APP Track license".
set security policies from-zone Trust to-zone Untrust policy Allow match dynamic-application any
If anything else is chosen, the security policy will NOT trigger, as SRX will fail to identify any application because the APPID database is not installed. This can lead to packet drops on SRX.