Your program had a set of features before you made changes and some of those features were changed. Some of the changes may be such that you will have to notify existing customers; others won't. It will depend on what you've told them before, what changed, and whether there's a regulatory requirement for a change in terms notice triggered.
One example -- Suppose that BEFORE you charged $35 per overdraft paid with no ceiling and no de minimis overdraft amount all properly disclosed under Reg DD, and AFTER you charge $35 per overdraft, with a three-fee ($105) maximum per day, and won't charge if the account is overdrawn $25 or less. Because both of the changes are beneficial to your customer, you don't need to provide a change in terms notice under Reg. DD (although you will arguably have to disclose the de minimis OD amount in your Reg DD account disclosures for new customers, and will have to disclose both the cap and the de minimis in disclosures under Reg. E §205.17).
If any of your fee amounts are being increased as part of the project, that will be adverse to the customer, so you'll have to do a change in terms notice for those changes.
_________________________
John S. Burnett
BankersOnline.com
Fighting for Compliance since 1976
Bankers' Threads User #8