The messages
- "Your plan includes this many people. Move to a bigger plan in Plan & billing to invite more. Everyone already here keeps their access.": the owner changes the plan in Settings → Plan & billing.
- "This business has reached its team size limit, so no one else can join right now.": shown to the person who tries to join.
- "You're in 10 businesses, the most one account can join. Close one you own to make room.": this limit is about the person's account, not your plan.
Does the owner count?
Yes. The number of users includes the owner.
What about my accountant?
A business covered by its accountant's Unlimited (accountants) plan gets Pro-level access, with nothing to buy or manage in the business itself.
Explanation written from the Deline app's own screens and texts (build eba146497 (Deline cf723fe1f)); it has no steps to check.