Please contact sales[at]bryntum.com for a refund and then buy the correct version at the app store.
https://apps.odoo.com/apps/modules/13.0/bryntum_gantt_enterprise/
Please contact sales[at]bryntum.com for a refund and then buy the correct version at the app store.
https://apps.odoo.com/apps/modules/13.0/bryntum_gantt_enterprise/