The ACE v3 plugin officially supports the IBM ACE version 11:
https://www.urbancode.com/plugindoc/app-connect-enterprise#tab-1-2
The use with ACE version 12 is not supported.
Not supported means that the integration with ACE v12 has not been tested.
It might work with the plugin, but if you face any problems, support might not be able to assist you, because this ACE version is not supported.
The best thing to do is to submit an idea for the plugin to support it:
https://cloud-platform.ideas.aha.io/ideas?project=URBANCODE
#Support#SupportMigration#UrbanCodeDeploy