Abstract: The field of the invention relates to systems and methods for selling seat upgrade capabilities, upgrading fan experience capabilities, connecting fan engagement activities provided by venues with the fans capabilities, and other services in an event or venue using an application or mobile browser. In an embodiment, during an event, a mobile upgrade and fan engagement system receives login information from a mobile device, retrieves account information based on the login information, receives information of a first purchased ticket, receives one or more upgrade selections from the mobile device, determines availability of one or more upgrades, displays the availability of one or more upgrades at the mobile device, receives one or more upgrade purchases based on availability, from the mobile device, completes payment for the one or more upgrade purchases, displays one or more upgrade electronic tickets at the mobile device, and releases the first purchased ticket for sale.