S3Drive - How to: Ultimate Business Plan, but with storage

How can I subscribe to the business plan and add some storage? My current understanding is that the storage plans include the Ultimate version for personal use only, though it doesn't specify on the website.

Thanks for your comment and sorry for the ambiguity. Ultimate as such is suited for personal use, regardless if bought as a standalone package or as a bonus to storage plan. Having said that, if you don't need couple additional features that come with Business plan you will be fine to use Ultimate even if it's within your organisation. We plan to make some changes in the future in that area. Recurring Ultimate will likely be available to anyone. Lifetime Ultimate will remain as it is (personal use), whereas Business plan will be suited towards companies with businesses specific needs... so instead of artificially controlling who can purchase the product, we will actually make packages which are more compelling for personal use and business use. (edited)

Then I think I'm good with a personal ultimate for now. S3Drive also works to copy/sync an on-device Android Seedvault backup (on GrapheneOS) to S3 storage, without breaking the backup creation process, like it happens occasionally when you write directly to Koofr webdav, for example. Android write for the S3 mount potentially would make this even easier in the future. For business use cases, user administration and management/deployment of secrets and such would likely be what admins need to provision S3Drive. StorJ is working on some file stream or fuse mount products, but focused on large media stuff only, afaik. Trying to keep the local user end point/client free from (corporate) files/content is a common goal that could be accomplished with S3Drive. This is where Google Drive file stream app is so convenient, and without much real competition aside from Insync on Linux. And no one does this reliably with open source e2e encryption yet.