[[breaking-changes-2.0]] == Breaking changes in 2.0 This section discusses the changes that you need to be aware of when migrating your application to Elasticsearch 2.0. [float] === Indices created before 0.90 Elasticsearch 2.0 can read indices created in version 0.90 and above. If any of your indices were created before 0.90 you will need to upgrade to the latest 1.x version of Elasticsearch first, in order to upgrade your indices or to delete the old indices. Elasticsearch will not start in the presence of old indices. [float] === Elasticsearch migration plugin We have provided the https://github.com/elastic/elasticsearch-migration[Elasticsearch migration plugin] to help you detect any issues that you may have when upgrading to Elasticsearch 2.0. Please install and run the plugin *before* upgrading. include::migrate_2_0/removals.asciidoc[] include::migrate_2_0/network.asciidoc[] include::migrate_2_0/striping.asciidoc[] include::migrate_2_0/mapping.asciidoc[] include::migrate_2_0/crud.asciidoc[] include::migrate_2_0/query_dsl.asciidoc[] include::migrate_2_0/search.asciidoc[] include::migrate_2_0/aggs.asciidoc[] include::migrate_2_0/parent_child.asciidoc[] include::migrate_2_0/scripting.asciidoc[] include::migrate_2_0/index_apis.asciidoc[] include::migrate_2_0/snapshot_restore.asciidoc[] include::migrate_2_0/packaging.asciidoc[] include::migrate_2_0/settings.asciidoc[] include::migrate_2_0/stats.asciidoc[] include::migrate_2_0/java.asciidoc[]