Does it? Reverting a bad deploy is not only about running the previous version.
Did you mess up data? Did you take actions on third party services that that need to be reverted? Did it have legal reprecursions?
It does. We’ve tried. No it’s not as easy as running the previous version.
I have written about this: https://swizec.com/blog/why-software-only-moves-forward/
> Takes ~10min to revert a bad deploy
A bad deploy can take way over that just in customer or partner management communication.
So, it makes sense if you have infinite testing budgets.
Personally, I prefer exhaustively testing the upgrade path, and investing in reducing the time it takes to push out a hot fix. Chicken bits are also good.
I haven’t heard of any real world situations where supporting downgrades of persistent formats led to best of class product stability.
Would love to hear of an example.
They might be an appropriate safeguard for a prototyping shop, but not for Delta.