It looks as though motherboards based on Intel's current generation Z370 chipset will support the chipmaker's upcoming 9th generation Core processor family by way of a BIOS update. We say this because at least two motherboard makers have already added BIOS updates for existing Z370 motherboards, with release notes suggesting they're intended for the next round of CPUs.
If you head over to MSI's website, for example, there are recent BIOS updates for its Z370 motherboards. One of them is for the Z370 Tomahawk—MSI uploaded an updated BIOS file (7B47v151) in beta form on July 13 that lists "Support New Generation CPU!" as the only change. Here's a screen grab, in case it disappears for some reason:
The new BIOS is not for Intel's commemorative Core i7-8086K processor, which isn't a next generation CPU anyway. But to make sure nothing got lost in translation, we looked up the motherboard's CPU support list and it shows the previous BIOS version (7B47v10) supporting the anniversary chip. It's pretty clear to us that the beta BIOS is intended for Intel's rumored Coffee Lake Refresh line.
ASUS is also pushing out updated BIOS software for its Z370 motherboard. We looked up the company's ROG Strix Z370-E Gaming and it shows a new BIOS (version 1002) being uploaded on July 6. There are two items in the release notes: "Improve system performance" and "Support the latest 8th Gen Intel Core Processor."
The wording is a little less clear, as is the "8th Gen" designation instead of 9th Gen. However, the CPU support list shows that Intel's Core i7-8086K processor has been validated to run on BIOS versions 0612 and later.
We know that Intel is preparing a new Z390 chipset because the company referenced it in support documents that were briefly visible to the public. One of those documents contained a block diagram as shown above. It's widely believed that the Z390 chipset will coincide with the release of Intel's new generation CPUs, but it looks as though it's not a big change over Z370. According to the block diagram, it introduces Wireless-AC and Bluetooth 5.0 support, along with support for USB 3.1.
There is also a rumor going around that those features might not be included in Z390, and that it will essentially be a rebranded Z370 chipset, perhaps with some minor power tweaks. Either way, it's looking increasingly likely that Z370 motherboard owners will be able to run Intel's upcoming 8-core/16-thread Coffee Lake Refresh processors on their existing hardware, if they're so inclined.