Upgrade your instance Upgrading and patching your instance requires planning, testing, and validation. To ensure a safe and effective upgrade, read the release notes, create upgrade plans, and test your upgrade on sub-production instances before upgrading your production instance. These topics contain in-depth explanations about upgrades. For a step-by-step reference of upgrade steps, refer to the Upgrade planning checklist (Istanbul). Phase 1 - Read the release notes and plan your upgradeBefore you begin the upgrade process, it is essential to read the release notes for your target version so you understand the required upgrade and migration tasks. This information helps you plan a safe and effective upgrade.Phase 2 - Prepare for the development instance upgradeFor a better understanding of your production upgrade duration, request a clone of your production instance onto a non-production instance that has similar hardware and your full database. Confirm your current and target release versions, because you will later use this information when scheduling your upgrade in HI.Phase 3 - Verify your upgrade configurations and schedule the development instance upgrade in HICheck the configuration of the Upgrade scheduled job to view how often and when it runs. Review information about timing your upgrade in coordination with the Upgrade scheduled job. Then, schedule your upgrade in HI.Phase 4 - Upgrade and validate the development instanceTrack the progress of your upgrades with the Upgrade Monitor. For your first non-production instance upgrade (your development instance), use the Upgrade Monitor to process the skipped list of records that were not addressed in the upgrade. Then identify your update sets and perform functional testing.Phase 5 - If applicable: Upgrade and validate your other non-production instances, such as your test instanceIf you have any other non-production instances in addition to your development instance, such as a test instance, request to upgrade these instances. Request these upgrades after you have configured and refined your development instance. Immediately after the upgrade is complete, apply the post-upgrade changes made to your development instance, including activating optional plugins, installing and upgrading applications, and applying update sets.Phase 6 - Prepare to upgrade the production instanceAfter you have configured and refined your test environment to be a good representation of your production environment, prepare to upgrade your production instance.Phase 7 - Upgrade the production instanceAfter you have upgraded your development, non-production, and test instances, upgrade your production instance last. Then validate that the upgrade was complete, apply update sets and fix scripts, and perform post-upgrade user acceptance testing (UAT).Troubleshooting and other upgrade resourcesUse this information to troubleshoot post-upgrade issues and learn more about other aspects of ServiceNow's upgrade process.