# Elasticsearch升级 > 重要 > > 开始升级Elasticsearch之前： > > - 查询[破坏性的改变](Breaking_changes.md)文档 > - Check the deprecation log to see if you are using any deprecated features. > - 如果你使用自己定义插件，请检查它可用的兼容版本。 > - 在升级生产环境之前先在开发环境做升级测试 > - 总是在升级前[备份你的数据](../Modules/Snapshot_And_Restore.md)，你**不能回滚**到早期版本，除非你有备份数据。 > Elasticsearch通过可以通过滚动升级来不中断服。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