I have received following answer from the KCC:
Thank you for your inquiry.
Based on the information you have provided, your interview location has been changed from Belgrade to Adjustment of Status. The new interview location will not appear on your DS-260, but will be used by KCC for scheduling purposes. When we have scheduled your interview, you will be required to log into the Entrant Status Check (ESC) to view your appointment notification. At that time, please verify that your appointment is scheduled for the correct post. If for any reason it is not, you may contact KCC again at KCCDV@state.gov. You will also need to request that KCC unlock your DS-260, so that you can update your application with your new address. (Please note that Post Office Boxes and mailing addresses in care of another person do not justify a change of interview location.)
I guess that, this is it, right?
Also, I'm kind of confused about this unlocking DS-260 part. Can someone explain why is that mentioned so? I will have a different address than one that I provided in DS-260 because I moved from that place, but I should be able to get that part done in I-485. I don't think that it is necessary to update DS-260, or am I wrong?
Thank you for your inquiry.
Based on the information you have provided, your interview location has been changed from Belgrade to Adjustment of Status. The new interview location will not appear on your DS-260, but will be used by KCC for scheduling purposes. When we have scheduled your interview, you will be required to log into the Entrant Status Check (ESC) to view your appointment notification. At that time, please verify that your appointment is scheduled for the correct post. If for any reason it is not, you may contact KCC again at KCCDV@state.gov. You will also need to request that KCC unlock your DS-260, so that you can update your application with your new address. (Please note that Post Office Boxes and mailing addresses in care of another person do not justify a change of interview location.)
I guess that, this is it, right?
Also, I'm kind of confused about this unlocking DS-260 part. Can someone explain why is that mentioned so? I will have a different address than one that I provided in DS-260 because I moved from that place, but I should be able to get that part done in I-485. I don't think that it is necessary to update DS-260, or am I wrong?