diff --git a/README.md b/README.md
index 40ad1b5..d024637 100644
--- a/README.md
+++ b/README.md
@@ -31,7 +31,7 @@ a distributed applications (e.g. with several servers, load balancers, etc.).
 The package could be installed with composer:
 
 ```
-composer require yiisoft/cache-memcached --prefer-dist
+composer require yiisoft/cache-memcached
 ```
 
 ## Configuration
@@ -124,47 +124,25 @@ To work with values in a more efficient manner, batch operations should be used:
 
 This package can be used as a cache handler for the [Yii Caching Library](https://github.com/yiisoft/cache).
 
-## Testing
+## Documentation
 
-### Unit testing
+- [Internals](docs/internals.md)
 
-The package is tested with [PHPUnit](https://phpunit.de/). To run tests:
-
-```shell
-./vendor/bin/phpunit
-```
-
-### Mutation testing
-
-The package tests are checked with [Infection](https://infection.github.io/) mutation framework. To run it:
-
-```shell
-./vendor/bin/infection
-```
-
-### Static analysis
+## License
 
-The code is statically analyzed with [Psalm](https://psalm.dev/). To run static analysis:
+The Yii Cache Library - Memcached Handler is free software. It is released under the terms of the BSD License.
+Please see [`LICENSE`](./LICENSE.md) for more information.
 
-```shell
-./vendor/bin/psalm
-```
+Maintained by [Yii Software](https://www.yiiframework.com/).
 
-### Support the project
+## Support the project
 
 [![Open Collective](https://img.shields.io/badge/Open%20Collective-sponsor-7eadf1?logo=open%20collective&logoColor=7eadf1&labelColor=555555)](https://opencollective.com/yiisoft)
 
-### Follow updates
+## Follow updates
 
 [![Official website](https://img.shields.io/badge/Powered_by-Yii_Framework-green.svg?style=flat)](https://www.yiiframework.com/)
 [![Twitter](https://img.shields.io/badge/twitter-follow-1DA1F2?logo=twitter&logoColor=1DA1F2&labelColor=555555?style=flat)](https://twitter.com/yiiframework)
 [![Telegram](https://img.shields.io/badge/telegram-join-1DA1F2?style=flat&logo=telegram)](https://t.me/yii3en)
 [![Facebook](https://img.shields.io/badge/facebook-join-1DA1F2?style=flat&logo=facebook&logoColor=ffffff)](https://www.facebook.com/groups/yiitalk)
 [![Slack](https://img.shields.io/badge/slack-join-1DA1F2?style=flat&logo=slack)](https://yiiframework.com/go/slack)
-
-## License
-
-The Yii Cache Library - Memcached Handler is free software. It is released under the terms of the BSD License.
-Please see [`LICENSE`](./LICENSE.md) for more information.
-
-Maintained by [Yii Software](https://www.yiiframework.com/).
diff --git a/docs/internals.md b/docs/internals.md
new file mode 100644
index 0000000..40fe5c5
--- /dev/null
+++ b/docs/internals.md
@@ -0,0 +1,57 @@
+# Internals
+
+## Development environment
+
+For greater ease it is recommended to use docker containers.
+
+Run container with memcached directly via command:
+
+```shell
+docker run --rm --name yiisoft-cache-memcached-cache --detach --publish 11211:11211 memcached:1.6.23
+```
+
+Memcached must be accessible by address `127.0.0.1`. If you use PHP via docker container, run PHP container in network
+of memcached container. Use `docker run` command argument for it:
+
+```
+--network container:yiisoft-cache-memcached-cache
+```
+
+## Unit testing
+
+The package is tested with [PHPUnit](https://phpunit.de/). To run tests:
+
+```shell
+./vendor/bin/phpunit
+```
+
+## Mutation testing
+
+The package tests are checked with [Infection](https://infection.github.io/) mutation framework with
+[Infection Static Analysis Plugin](https://github.com/Roave/infection-static-analysis-plugin). To run it:
+
+```shell
+./vendor/bin/roave-infection-static-analysis-plugin
+```
+
+## Static analysis
+
+The code is statically analyzed with [Psalm](https://psalm.dev/). To run static analysis:
+
+```shell
+./vendor/bin/psalm
+```
+
+## Code style
+
+Use [Rector](https://github.com/rectorphp/rector) to make codebase follow some specific rules or
+use either newest or any specific version of PHP:
+
+```shell
+./vendor/bin/rector
+```
+
+## Dependencies
+
+Use [ComposerRequireChecker](https://github.com/maglnet/ComposerRequireChecker) to detect transitive
+[Composer](https://getcomposer.org/) dependencies.