Hi there, @raleighhobson.
Please allow me to join the thread and help share additional information about reminders in QuickBooks Online (QBO).
Whatever features available in the lower versions of QBO, will also be available in QBO Advanced. Therefore, you have the option to send reminders to your customers for the overdue invoices using the Advanced version.
To send reminders manually:
To learn more about the QBO versions and features, you may check this article: Compare Online Versions of QuickBooks.
As always, I'll be always here to help you if you have any other questions about reminders, just add a post/comment below. Wishing you the best!