The perspective is not so good, but it seems to have a center gear, so it really must be the A340-500 (HS-TYV). I first thought it is a B737.
The RTAF does have a passenger jet fleet of some Airbus 319/320's, some B737's and one A340-500. There are also 3 Sukhoi Superjets 100, which do not seems to see a lot of flying.... (see wikipedia: https://en.wikipedia.org/wiki/List_of_aircraft_of_the_Royal_Thai_Air_Force)
Which one of those they want to replace is not clear. Whoever wrote that article does not really have a particularly deep knowledge of aviation.
The A340 has flown to Turkey a couple of times lately, I suppose on humanitarian missions. As far as I know from FR24, it has also spent quite some time in Lufthansa's workshop in Hamburg last year - probably for upgrades inside and out. So I somehow doubt it is up for replacement.