It's back to business as usual for MARTA customers.

But if you traveled Sunday morning, it was a good idea to have some cash.

A routine software upgrade of MARTA's Breeze system prevented riders from using the credit/debit feature between 1 a.m. and 9 a.m. Sunday, a transit authority spokeswoman said. The system was scheduled to be back online after 9 a.m.

The upgrade is complete and customers are able to use the credit/debit feature again, a spokeswoman told the AJC Sunday afternoon.