From my understanding, IP addresses are only considered personal data if and only if the IP address can be tied to a specific individual. ZeroTier cannot do that. We can tie an IP address to a ZeroTier Identity.
If that identity is joined to a network controller that we host, we know the Identity is in use on a network owned by firstname.lastname@example.org. We have no way of knowing if it is Bob using ZeroTier on the the machine, his wife, his friend, or whoever. We don’t even know if it’s Bob’s personal machine, his wife’s, friend’s, etc. To us, it’s just a machine joined to a network that we host.
You also don’t have to use our hosted controllers to use ZeroTier. Mac/Windows/BSD/Linux versions of ZeroTier are all capable of being network controllers themselves. https://github.com/zerotier/ZeroTierOne/tree/master/controller
If that identity is joined only to user hosted network controllers, all we know is that Node A has IP address X.X.X.X, and what other machines running ZeroTier it needs to find to communicate with. We cannot derive any other information than that.
If you request your data from us, all we could give you is what’s already available when you log in at https://my.zerotier.com because that’s all we collect about individuals. If you log in to https://my.zerotier.com and delete your account, then that’s it. The data is removed from the database. Full stop.