diff --git a/BREAKING_CHANGES.md b/BREAKING_CHANGES.md
index 4cd3b2154..03e572546 100644
--- a/BREAKING_CHANGES.md
+++ b/BREAKING_CHANGES.md
@@ -1,21 +1,41 @@
 # 8.0
 
 This major release is a complete new PHP client for Elasticsearch. We build it from scratch!
-We tried to reduce the BC breaks as much as possible but there are some big differences :rage: 
+We tried to reduce the BC breaks as much as possible but there are some (big) differences: 
 
 ## Architectural changes:
 
 - we changed the namespace, now everything is under `Elastic\Elasticsearch`;
-- we used the [elastic-transport-php](https://github.com/elastic/elastic-transport-php) library
-  to manage the HTTP requests and responses; This library allows the usage of any [PSR-18](https://www.php-fig.org/psr/psr-18/)
-  client.
-- we changed the response type of each endpoints using a wrapper class of a [PSR-7](https://www.php-fig.org/psr/psr-7/)
-  response. This class allows the access of the body response as array or object. This means
-  you can access the API response as in 7.x, no BC break here! :angel:
+- we used the [elastic-transport-php](https://github.com/elastic/elastic-transport-php) library for HTTP communications;
+- we changed the `Exception` model, using the namespace `Elastic\Elasticsearch\Exception`. All the exceptions extends the
+  `ElasticsearchException` interface, as in 7.x;
+- we changed the response type of each endpoints using an [Elasticsearch](src/Response/Elasticsearch.php) response class.
+  This class wraps a a [PSR-7](https://www.php-fig.org/psr/psr-7/) response allowing the access of the body response
+  as array or object. This means you can access the API response as in 7.x, no BC break here! :angel:
 
 ## Specific changes:
 
-- to be completed 
+The following functions has been removed:
+
+- `ClientBuilder::getEndpoint()`
+- `ClientBuilder::getRegisteredNamespacesBuilders()`
+- `ClientBuilder::getRegisteredNamespacesBuilders()`
+- `ClientBuilder::defaultHandler()`
+- `ClientBuilder::multiHandler()`
+- `ClientBuilder::singleHandler()`
+- `ClientBuilder::setConnectionFactory()`
+- `ClientBuilder::setConnectionPool()`
+- `ClientBuilder::setEndpoint()`
+- `ClientBuilder::registerNamespace()`
+- `ClientBuilder::setTransport()`, you can specify an HTTP PSR-18 client using `ClientBuilder::setHttpClient()`
+- `ClientBuilder::setHandler()`
+- `ClientBuilder::setTracer()`, you can only set a Logger using  `ClientBuilder::setLogger()`
+- `ClientBuilder::setSerializer()`
+- `ClientBuilder::setConnectionParams()`, you can use `ClientBuilder::setHttpClientOptions()` instead
+- `ClientBuilder::setSelector()`
+- `ClientBuilder::setSniffOnStart()`
+- `ClientBuilder::includePortInHostHeader()`
+
 # 7.17
 
 - We changed the signature of `Elasticsearch\Common\EmptyLogger::log` adding the `void` return type.
diff --git a/README.md b/README.md
index fdb73af79..04c345159 100644
--- a/README.md
+++ b/README.md
@@ -5,6 +5,8 @@ Elasticsearch PHP client
 
 [![Build status](https://github.com/elastic/elasticsearch-php/workflows/PHP%20test/badge.svg)](https://github.com/elastic/elasticsearch-php/actions) [![Latest Stable Version](https://poser.pugx.org/elasticsearch/elasticsearch/v/stable)](https://packagist.org/packages/elasticsearch/elasticsearch) [![Total Downloads](https://poser.pugx.org/elasticsearch/elasticsearch/downloads)](https://packagist.org/packages/elasticsearch/elasticsearch)
 
+This is the official PHP client for connecting to [Elasticsearch](https://www.elastic.co/elasticsearch/).
+
 ## Contents
 
 - [Getting started](#getting-started-)
@@ -85,7 +87,23 @@ For more information about the Elasticsearch REST API you can read the official
 
 ## Backward Incompatible Changes :boom:
 
-To be completed
+The 8.0.0 version of `elasticsearch-php` contains a new implementation compared with 7.x.
+It supports [PSR-7](https://www.php-fig.org/psr/psr-7/) for HTTP messages and [PSR-18](https://www.php-fig.org/psr/psr-18/)
+for HTTP client communications. 
+
+We tried to reduce the BC breaks as much as possible with `7.x` but there are some (big) differences:
+
+- we changed the namespace, now everything is under `Elastic\Elasticsearch`;
+- we used the [elastic-transport-php](https://github.com/elastic/elastic-transport-php) library for HTTP communications;
+- we changed the `Exception` model, using the namespace `Elastic\Elasticsearch\Exception`. All the exceptions extends the
+  `ElasticsearchException` interface, as in 7.x;
+- we changed the response type of each endpoints using an [Elasticsearch](src/Response/Elasticsearch.php) response class.
+  This class wraps a a [PSR-7](https://www.php-fig.org/psr/psr-7/) response allowing the access of the body response
+  as array or object. This means you can access the API response as in 7.x, no BC break here! :angel:
+
+You can have a look at the [BREAKING_CHANGES](BREAKING_CHANGES.md) file for more information.
+
+## Specific changes:
 
 ## FAQ 🔮