First, I recommend upgrading to the latest 184.108.40.206 release.
There is nothing you have to do on the server to get a client to use passive mode. That’s a client decision. Most modern clients will try passive mode first.
You may have to adjust what IP address is given out for FTP vs FTPS connections. Generally, you have to give out the external IP address for passive responses with FTPS connections. For FTP, you may have to manually specify the local IP address.