I have researched here many times, posted a few and solved some NVME drive problems because of it. I am still running Win7 on my business computer as there are several older programs of great value to my business which may not run on a newer OS. Because of the soon to end Microsoft support for Win7, I now have no choice but to move up. I wanted to upgrade to Win8 to maintain my programs and settings. A clean install of Win8 (or 10 for that matter) would require installing over 90 programs on the new OS, creating days of reactivating software and tweaking each program from their default settings.
I have successfully used the upgrade path to Win8 then on to Win8.1 for two desktop computers, each with SSD’s. All my programs and settings came over as expected with minor adjustments needed. I now have my last computer which has a Z270 Asus motherboard and two m.2 Adata SX8200 Pro NVME drives. Everything works great under Win7 as I long ago used advice from here to get that installed on the NVME drives. Also, those two NVME drives are partitioned as GPT disks which I believe means they cannot be cloned as I used to do with SSDs.
My problem is that part of the upgrade path involves a compatibility check for Win8 and it indicates I need to update the Standard NVME controller from MS in order to proceed. Of course there is no such update from MS (that I know of). I have tried forcing the Intel RST v16 driver which has a NVME driver with the same failed result. I also tried the OFA 1.5 NVME driver which caused my system to stop booting. That path took 9 hours to get back to using the MS driver and involved restoring my backup image.
After much searching I have come to the conclusion that the Win8 upgrade program does not have a native NVME driver (I read Win8.1 does) and therefore it fumbles the compatibility tests. It’s not so much about the NVME driver but more about the missing information in the compatibility program about a newer technology. Does anyone know of a way around the Win8 programing that is stopping my upgrade from Win7? If given detailed instructions I can usually tackle these software issues.
I would appreciate your input. 
@NM_Acct :
Since Win8/8.1 have native NVMe support by a generic MS in-box driver, it should be no problem to upgrade from Win7 to Win8/8.1.
How did you do it and what kind of failure did you get?
This is why I recommend to set a "Restore Point" before updating the storage driver, which manages the system drive and the Windows Boot Manager.
By the way: The mod+signed OFA NVMe driver v1.5.0.0 works fine for me as long as the "Fast Boot" option is disabled within the BIOS and the hiberfile.sys has been deleted.
Fernando,
Thank you for your quick reply. In everything I have read, the generic MS driver was not added until Win8.1 but since I trust your knowledge, I can’t understand why the Win8 compatibility check says it needs updating. Is there only one version of that generic NVME driver? Perhaps I have an older version which is 6.1.76… I believe.
I forced the Intel driver through device manager “have disk” method and it did update. Still the Win8 compatibility check gave the same “you must update this driver” for update to continue, concerning the Intel.
I agree that OFA 1.5 as well as the other two I tried should work fine in Win8. It seems to be just the compatibility tool that stops the upgrade. I was hoping someone had found a way to force the install to continue as an upgrade. And for all I know, a clean install of Win8 might have a problem installing on a NVME drive??
@NM_Acct :
You may be right regarding the missing native NVMe support of Win8. So you should better directly upgrade to Win8.1.
EDIT: It is possible to get a mod+signed (OFA) or not 100% matching (Intel RST) storage driver installed onto an already running OS, but the Setup of a modern Windows OS generally doesn’t accept such drivers.
My statement: You are wasting a lot of time trying to do an upgrade from Win7 to a more modern Windows OS, but you cannot be sure, that you will succeed.
My tip: Save the important data of your NVMe SSD, additionally do a backup of the complete system drive (OS+Boot sector). Then do a fresh install of Win10 v19H1 or 19H2.
Big advance: Only this way you can be sure, that your NVMe SSD will work properly and that you get rid of all the garbage from your previous usage and updates.