Classic Nintex Form and application being executed in Microsoft 365 environment.

I have an application that is running in an On premises environment. The OS and mail services have now been upgrade to a Microsoft 365 environment. I am seeing some unexpected behaviors in the forms and some of the mail actions. My question is if there is something that need to be done for an application that was running in the On-Premise environment that is now executing in the Microsoft 0365 environment. Is there any type of migration that need to be done for the application to run as created in the Microsoft 0365 environment that is not migrated into the Nintex cloud (NWC).