Update README.md

Author: sokil

README.md

@@ -116,18 +116,11 @@ Download latest release:
 > To start using PHPMongo with PHP7, add requirement [alcaeus/mongo-php-adapter](https://github.com/alcaeus/mongo-php-adapter) to composer.
 > Restrictions for using ODM with compatibility layer you can read in [known issues](https://github.com/alcaeus/mongo-php-adapter#known-issues) of original adapter.
 
-Library `sokil/php-mongo` depends from old `ext-mongo` so you need to require dependency with `--ignore-platform-reqs` flag:
-```
-composer require sokil/php-mongo --ignore-platform-reqs
-```
-
-Also you need to require adapter of old `ext-mongo` API to new `ext-mongodb`:
+Require adapter of old `ext-mongo` API to new `ext-mongodb`:
 ```
 composer require alcaeus/mongo-php-adapter
 ```
 
-
-
 #### Symfony bundle
 If you use Symfony framework, you can use [Symfony MongoDB Bundle](https://github.com/sokil/php-mongo-bundle) which wraps this library