During an upgrade, FusionAuth monitors your deployment, and if it becomes unresponsive for more than five minutes, the on-call engineer is alerted. A snapshot of the database is taken before the upgrade, so a rollback is possible, though it is manual and would result in data loss from the time of the upgrade to the rollback. Rollbacks are very rare and have only happened once in the past four years.
You can safely upgrade directly to 1.59, and many customers do skip versions. The upgrade process is straightforward: once started, the deployment status changes to Upgrading and returns to Active when complete. For production instances, downtime is minimal (typically seconds, if at all) because multi-node deployments use rolling upgrades. Most upgrades take under 20 minutes, though in rare cases they can take up to an hour.
FusionAuth never forces you to upgrade, but if you are running a very old version (1–2 years behind) and encounter issues, support may request that you upgrade before troubleshooting.
Upgrading a Deployment