Our initial feature for syncing invoices from QuickBooks Online to Viewpost has the following limitations.
1. Invoices dated up to 1 year prior to current date can be synced
2. Credit memos cannot by synced...yet.
3. Customer payments received outside of Viewpost and recorded in QBO do not sync to Viewpost yet. You will need to log in to Viewpost and manually record the payment. See https://support.viewpost.com/hc/en-us/articles/218645498-How-Do-I-Record-a-Payment-Received-on-an-Invoice
4. Customer payments received through Viewpost do not sync to QBO yet. You will need to manually record the payment in QBO.
5. Shipping addresses do not appear on the Viewpost invoice but will in the near future.
We will be releasing new features regularly so watch for our improvements.