We've talked about this at length. In summary:
- We need to pay for various bits of infastructure that support C3. Users on old versions not upgrading would be an ongoing cost us
- We'd need to patch old versions when breaking changes happen - this can be really difficult
- We'd struggle to offer support to these users. Saying "support only for newest version" doesn't cut it imo.
There'd be a lot of changes and complications our end - all so people wouldn't need to pay any more. It's not something we're looking at doing.