As VideoCardz reports, this is further evidence that the Z370 will be getting an improved version. The only Z390 motherboard from MSI that's been rumored so far is the Z390 GAMING PLUS.
AIDA64 Version: 5.95.4569 beta (Mar 09, 2018):extended chipset information for Intel Skylake-D/SP/W/X IMC sensor support for Nuvoton NCT6797D motherboard specific sensor info for ASRock H110M-STX motherboard specific sensor info for ASRock Z370M-STX MXM motherboard specific sensor info for MSI B360/H310/H370/Z390-Series fixed: motherboard specific sensor info for Asus Maximus IX/X Series fixed: motherboard specific sensor info for Asus Prime Z270-A, Prime Z270-AR, Prime Z370-A, ROG Strix Z370-E Gaming, ROG Strix Z370-F Gaming, Strix B250F Gaming, Strix Z270E Gaming, Strix Z270F Gaming, Z270-WS