LTO-8 Drives will start shipping in Q12018. As usual there is a capacity increase in LTO-8 drives ( 12TB Native, double that of LTO-7), but this is not the only differentiating factor for this new drive.  

For the first time, you will be to use an LTO-7 Media  in LTO-8 drive with 9TB Capacity - 50% more than you would get in LTO-7 Drive.  This is similar to 3590 or 3592 Media where the same media yields different capacities in different drives. 

• LTO-7 Media has to be new and previously unused 
• It will have to be formatted as LTO-8 Type M media. It will only work in LTO-8 drive once formatted in such a way
• If LTO-7 Media that has been previously formatted on LTO-7 drive is used in LTO-8, it would yield the same 6TB Capacity. 

The table below shows the compatibiltiy and possible use of LTO-7 media in LTO-7/8 drives. 

This means that simply by upgrading to an LTO-8 driver, the custmer can realize the benefit of an increased capacity, even with their existing (new and unused) inventories of LTO-7 Media.