Tenant Resisting Autopay

[Jennifer Jackson]

I purchased a property with existing tenants. Currently, each of them puts their rent in a dropbox. We changed this method to an online system. All of our tenants have signed up except one, who refuses to use the system. (He also pays using money order, which is less than ideal since we have to go to the bank to deposit it). 

Is there a way I can legally make the tenant use the online system before his current lease is up, or will I just need to wait it out?
Thanks!