Maintenance covers monitoring of the delivered scope, break/fix work, ordinary vendor/API/platform compatibility remediation required to keep that scope working, and bounded improvements within the implemented boundary.
Vendor-driven replacement or migration, substantial redesign, new systems, material new functionality and third-party SaaS/API/platform fees are separately scoped or charged.
After the initial three maintenance months, maintenance continues month-to-month unless cancelled before the next billing date under the service terms.