Starting from elasticsearch-php 7.4.0, we generate a PHP [E_USER_DEPRECATED](https://www.php.net/manual/en/errorfunc.constants.php) notice every time you use a deprecated parameters for Elasticsearch. We decided to add this notice to facilitate the code refactoring with the new API specification of Elasticsearch (e.g. the usage of typeless APIs, see below).
Elasticsearch 7.0 deprecated APIs that accept types, introduced new typeless APIs, and removed support for the default mapping. Read [this](https://www.elastic.co/blog/moving-from-types-to-typeless-apis-in-elasticsearch-7-0) blog post for more information.
Added type hints and return type declarations in all the code base, where possible. See PR [#897](https://github.com/elastic/elasticsearch-php/pull/897).