I do notice in their GUI that they offer a >30 memory for extra $:
30-Day Version History (Current) Included
1-Year Version History
Forever Version History $.006/GB/Month for versions changed or deleted more than 1 year ago
They are not giving much information here at all. The above is not a pasting artifact; their page literally doesn't give any indication of how they price the 1-year history. Presumably it's not just as simple as click to 12x your retention for free.
Meanwhile, it's even more unclear whether that $.006/GB is assessed for change deltas or for the total file size. Indeed, it's not clear if it's assessed against your entire fileset or just files that changed.
I'll have to email them, I guess.
https://www.reddit.com/r/backblaze/comments/175haik/is_upgra...
(Ironic that their ex-employee wrote: "In this case, it is always kind of scary for Backblaze to just quietly change a setting from one setting to a different setting in the product for the customer without the customer taking that action themselves." — when that's what happened in this case.)
I don't use Backblaze, but I found the Version History doc for you:
https://www.backblaze.com/computer-backup/docs/version-histo...
Seems like whatever version is not currently on your local disk would be chargeable.