when you purchase Studio 17 what about Studio 18, 19...

What are the terms when one buys Resolve Studio 17?
How long are upgrades included? Does it include a free right to upgrade to future versions,
say Studio 18 or 19? Is there a limit?
Or is it just for Studio 17, and we get to pay for an upgrade to future releases?
Is there a track record for this?
(I don't expect Blackmagic to comment about future product plans)
How long are upgrades included? Does it include a free right to upgrade to future versions,
say Studio 18 or 19? Is there a limit?
Or is it just for Studio 17, and we get to pay for an upgrade to future releases?
Is there a track record for this?
(I don't expect Blackmagic to comment about future product plans)