diff --git a/README.md b/README.md
index 0ddb544..c5c3b3c 100644
--- a/README.md
+++ b/README.md
@@ -109,7 +109,8 @@ config.middleware.use IdempotentRequest::Middleware,
   header_key: 'X-Qonto-Idempotency-Key', # by default Idempotency-key
   policy: IdempotentRequest::Policy,
   callback: IdempotentRequest::RailsCallback,
-  storage: IdempotentRequest::RedisStorage.new(::Redis.current, expire_time: 1.day, namespace: 'idempotency_keys')
+  storage: IdempotentRequest::RedisStorage.new(::Redis.current, expire_time: 1.day, namespace: 'idempotency_keys'),
+  conflict_response_status: 409
 ```
 
 ### Policy
@@ -134,7 +135,7 @@ end
 
 ### Callback
 
-Get notified when the client sends a request with the same idempotency key:
+Get notified when a client sends a request with the same idempotency key:
 
 ```ruby
 class RailsCallback
@@ -150,6 +151,10 @@ class RailsCallback
 end
 ```
 
+### Conflict response status
+
+Define http status code that should be returned when a client sends concurrent requests with the same idempotency key.
+
 ## Contributing
 
 Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/idempotent-request. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](http://contributor-covenant.org) code of conduct.