The best time to start preparing for a ServiceNow upgrade is well before the release date is announced. Teams that treat upgrade readiness as an ongoing discipline consistently see faster, cleaner upgrades.
Review the release notes early
ServiceNow publishes release notes well ahead of general availability. Pay particular attention to deprecation notices — APIs flagged as deprecated are typically removed within two to three releases.
Run the Upgrade Center preview regularly
Running upgrade previews quarterly gives you visibility into how your customizations are affected over time. The preview becomes a health monitoring tool, not just a pre-upgrade checklist item.
Manage your customization footprint
Document why each customization exists, regularly audit them to identify any no longer needed, and where possible use scoped applications rather than modifying out-of-box records directly.
Build automated test coverage before you need it
Start with your highest-criticality workflows and expand ATF coverage over time. Even partial coverage significantly reduces the manual testing burden at upgrade time.
Establish an upgrade cadence
Organizations that upgrade on a regular schedule find each individual upgrade easier than those that defer across multiple release cycles. Staying current is almost always less work in the long run.