We did consult with lawyers who specialize in GDPR issues via NumFocus on this matter and gave them a detailed list of what data we send. This was their conclusion:
The inquiry as to which operating system is used, the fact that the IP-address is recognized by the server and that the used Julia version is surveyed is justified – without consent.
However, these surveys represent processing operations that must be disclosed to the user. The creation of the user-ID of the users seems to us to be justifiable as well (given that further information about the purpose / benefit of the processing will be sustainable within the consideration of the interests).
We recommend implementing a link on the Julia start display that lets users know about the data surveys in question and informs about the facts as stated above, so that the duty to inform subjects is fulfilled in accordance with Art. 13 GDPR.
As you can see, we are following this recommendation by printing a legal notice the first time the user does a package operation which sends telemetry data, informing the user that data is sent to the server and linking to a page with a detailed account of what data is sent, why it is collected, what it is used for, and how to opt out.
Regarding the quote you posted from “i-scoop.eu”, there is important context necessary: it’s generally assumed on sites like that the service in question also collects personally identifying information about users and that the IP address can be linked with that data. In such a context, since the IP address can be tied back to the user’s identity, it becomes personal data as well. On the other hand, if no personally identifying data is collected, then the IP address lacks significance as personal data. Otherwise the GDPR would require notifying anyone who connects to any server on the internet in any capacity. At least that is my understanding as a non-lawyer who has read quite a lot on the subject and gone back and forth with lawyers about this quite a bit.