From version 3.4 on, Zentyal can provide an ActiveSync gateway on top of its OpenChange module.

There is one package available which provide this functionality, sogo-activesync.

You will need to have zentyal-openchange installed and enabled.

Using the command line:

sudo apt-get install sogo-activesync

Once you have installed one of the packages, you will be able to enable or disable the ActiveSync option from the OpenChange configuration on the Zentyal interface.