For a very long time, we had only one mirror which was hardcoded into default configuration. But now we have two mirrors, and I'm hoping we will have more in the future. So it's time to remove the hardcode and make mirror selection configurable.
Unfortunately this is not as easy as it sounds, as it requires two changes to do so. We cannot push both of them at once, because it will break package manager operations (install, upgrade etc.). We pushed the first change today as a new configuration file which is not enabled yet. The next change will be to actually enable the configuration file for all our users.
All you have to do is keep the system updated. This way the transition will be seamless, you won't even notice it. However, if your system is out of date, the second change will most likely break package manager operations, as stated above.
We plan to enable the new configuration file in exactly 10 days, on January 28th. Please make sure your system is up to date by that time.