Move from on_permissive GTID to full GTID


We’re currently moving from MySQL 5.6 (no GTID) to MySQL 5.7 (end goal, full GTID)

Right now, I’ve got this setup:

| - master1 (5.6.19, GTID OFF)
| slave1 (5.6.19, GTID OFF)
| slave2 (5.6.19, GTID OFF)
| - new-master1 (5.7.13, GTID ON_PERMISSIVE)
| - new-slave1 (5.7.13, GTID ON_PERMISSIVE)
| - new-slave2 (5.7.13, GTID ON_PERMISSIVE)

The new master is a slave of the old master, and, the new slaves are slaves of the new master.

What I want to know is what are the next steps to move the whole new server to GTID = ON?

Is there a way that the new slaves can be ON, but, new master remains ON_PERMISSIVE and then when we have our full cut over maintenance it’s changed then?

Thanks in advance,