Originally Posted by
RadioSaigon
I would assume both of the renamed airports still had unique ICAO identifiers
I wouldn't be so sure - associating an ICAO identifier with the as-yet-unopened new airport would be very unusual and, in this case, jumping the gun. So, while the intent may well be to re-allocate FLSK to the new Simon Kapwepwe Airport once it opens, at present it still relates to the existing airport.
It's possible, though unlikely, that the provider Ethiopian uses for FMS data may have implemented that change prematurely.
The previous code for the current airport - FLND - hasn't been a current ICAO code (per Doc 7910) for the last 10 years or so, notwithstanding what
Wikipedia thinks.