We are currently on 6.5u4 and we are starting to plan for upgrade to 7.0. If I am not mistaken there are specific ports that need to be opened for Zerto 7 as the billing model has changed.
Please scroll to the bottom of the following article for the billing requirements in Zerto 7.0:
Is it gonna be the same config for 7.5?
Let us confirm that internally and get back to you.
We have confirmed that the requirements will not be changing in Zerto 7.5