When did Gree happy ever after come out?

in p>21. According to the introduction of Gree official website, it is known that Gree happy ever after produced in 21. Gree Air Conditioning happy ever after has an intelligent sleeping system, which is equipped with the international leading 1 Hz low frequency control technology. At the same time, it has four sleep modes, namely, sleep mode, wake-up mode, nap mode and DIY mode, to meet the needs of various sleep conditions. Six kinds of Gree patented humidity control systems, linkage humidity control is more accurate; The intelligent optimal sleep system includes five technologies: 2 dB intelligent control, original ventilation and breathing technology, national patented intelligent humidity control technology, national patented sleep technology and 2.4G radio frequency technology.