503 Application Number and Filing Receipt [R-07.2022]

Application numbers consisting of a series code and a serial number are assigned by the Office of Patent Application Processing (OPAP) immediately after mail has been opened. If an application is filed using the USPTO patent electronic filing system, EFS-Web provides an Acknowledgement Receipt that contains a time and date stamp, an application number and a confirmation number.

The following series codes are assigned to the applications identified below: