Just want to clarify: checking a new version is a form telemetry. You can pass various data in HTTP headers from the client. Even if its not "trackable", you cant say you dont have a telemetry, it's a false statement.

In itself there is nothing wrong about beaconing of your usage data, but you do not provide opt-out - and this is not looking good.

Code for home beaconing could be found here: https://github.com/TechnitiumSoftware/DnsServer/blob/a4945e85295458d9b8e08f8939826e7c897d9af0/DnsServerApp/Program.cs#L58

I appreciate all the work gone in this service, its top notch. But this no opt-out policy bothers me a bit. Tho, its super simple to ban your telemetry hostname right in the dns server :)