Waiting for QRZ to recognize my new callsign . (K2KIX to the new call K2KDX) Will I have to change anything in order to upload and download LOTW?
Yes. Review the Logbook Help files for all the details but you'll need a new QRZ Logbook for your new callsign and go through the process with the ARRL for your new callsign. Also review the ARRL LoTW help.