For a few months now I have received Xero invoices with due date the same as the invoice date. Their email says the payment will be collected from the account ten days later.

Up until then the due date was the same as the payment date. This is annoying because the invoices show as overdue even though payment is automatic from their side:

When you click the invoice link from the email you can add to your account. This month it came up with a warning about multi-currency. The warning is not clear as they say Xero (NZ) Ltd is not enabled for multi-currency but I should upgrade to enable multi-currency on my account.

Sure, it could be just an error on their part (Hanlon's razor), but the cynic could say it's them trying to push a paid upgrade that's unnecessary. 

Mildly annoying but unnecessary stress.

Raised a case with their support, which is a waste of time for everyone but if you don't point out faults, it won't get fixed.