[[elasticsearch-migration-guide-5.0-5.1]]
= Upgrading from 5.0.x to 5.1.x

This section describes breaking changes from version 5.0.x to 5.1.x and how removed features can be replaced by new introduced features.

[[elasticsearch-migration-guide-5.0-5.1.breaking-changes]]
== Breaking Changes

In the `org.springframework.data.elasticsearch.core.index.AliasData` class, which is used for alias information returned from Elasticsearch, the property `filter` (of type `Document`) is replaced by `filterQuery` which is of type
`org.springframework.data.elasticsearch.core.query.Query`.

`org.springframework.data.elasticsearch.annotations.Similarity` was an enum class until 5.1. This enum was used in the `@Field` annotation to specify a similarity value.
But besides the values defined by the enum, it is possible to have similarities with custom names in Elasticsearch.
Therefore, the annotation property was changed from the type of the enum to a simple `String`.
The previous enum values like `Similarity.Default` do still exist as String constants, so existing code will compile unmodified.
Adaptions are necessary when this enum was used at other places than as a property of the `@Field` annotation.
