Removing a domain now frees its email too

Removing a custom domain used to release only half of it. If you had set email up on that domain, the mail side kept holding the name: one domain belongs to one account, permanently, because two accounts sharing a mail domain would be two accounts able to read each other's mail. So the domain looked disconnected, and setting it up on another store answered "that domain is already served by another organisation" — with nothing you could do about it from your own dashboard.

Added

• Remove email from a domain. In Settings → Domains → Email from your domain, each configured domain now has a remove action. It asks first, and it says what goes: a sending domain stops sending as your address and falls back to noreply@platformdtc.com; a full-mailbox domain loses its mailboxes and the mail in them.
• Removing the domain removes its email too. Disconnecting a custom domain now releases the matching mail setup automatically, so the name is immediately usable on another store or another account.
• A confirmation before a domain is removed. Removing a domain was one unconfirmed click. It now asks, and when the domain carries your email it says so in the dialog, before anything is torn down.

Kept safe

• Your other addresses are untouched. Email lives on the root domain, so if you have both brand.com and shop.brand.com connected, removing one of them leaves the email alone — it is only released when the last hostname on that domain goes.
• Nothing is released while it might still be receiving. If the mail service cannot be reached, the removal reports a failure and changes nothing rather than freeing a name whose mailboxes are still live.