# Elasticsearch升級 > 重要 > > 開始升級Elasticsearch之前： > > - 查詢[破壞性的改變](Breaking_changes.md)文檔 > - Check the deprecation log to see if you are using any deprecated features. > - 如果你使用自己定義插件，請檢查它可用的兼容版本。 > - 在升級生產環境之前先在開發環境做升級測試 > - 總是在升級前[備份你的數據](../Modules/Snapshot_And_Restore.md)，你**不能回滾**到早期版本，除非你有備份數據。 > Elasticsearch通過可以通過滾動升級來不中斷服。However, you might need to?[Reindex to upgrade](https://www.elastic.co/guide/en/elasticsearch/reference/6.0/reindex-upgrade.html "Reindex before upgrading")?indices created in older versions. Upgrades across major versions prior to 6.0 require a?[Full cluster restart](https://www.elastic.co/guide/en/elasticsearch/reference/6.0/restart-upgrade.html "Full cluster restart upgrade"). The following table shows when you can perform a rolling upgrade, when you need to reindex or delete old indices, and when a full cluster restart is required. // TODO