Arduino IDE contacts external server on startup

Can someone explain why the Arduino IDE is connecting to on TCP port 80 (http) anytime the program starts up?

I've started "denying until quit", and now the Firefly module I was having "device busy" issues with, is working fine. :-?

To check for updates perhaps? but I don't understand why blocking it has apparently solved the bt problem.

Look in the preferences.

"Check for updates on startup"

Apologies for that - it's a feature left over from Processing. We don't actually use it, but I forgot to remove it.