diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..01109d4
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2023 museum-digital
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..421ab0a
--- /dev/null
+++ b/README.md
@@ -0,0 +1,19 @@
+# Quality Assurance Settings for museum-digital
+
+Most of the code used at [museum-digital](https://www.museum-digital.org) is written in PHP. To keep a uniform code style throughout the code, we use [PHP Code Sniffer](https://github.com/squizlabs/PHP_CodeSniffer).
+
+## Tools used
+
+- [php-codesniffer](https://github.com/squizlabs/PHP_CodeSniffer)
+- [PHPStan - PHP Static Analysis Tool](https://github.com/phpstan/phpstan)
+- [phpunit](https://phpunit.de/)
+
+## This Repository
+
+This repository serves to collect generally applicable rules, that can be embedded into the specific rule sets of the different projects.
+
+The file [`md_phpcs_rules.xml`](./rules/md_phpcs_rules.xml) contains the main style guide. When rewriting files to fit the uniform style rules, [`md_phpcs_rules_basic.xml`](./rules/md_phpcs_rules_basic.xml) comes in handy as a first step. It contains the same rules, excluding some which require or encourage a more in-depth look at the code (the prohibition of procedural-style calls to mysqli functions is e.g. a good opportunity to check the efficiency of queries).
+
+## License
+
+This project is licensed under the MIT License. See the [LICENSE](./LICENSE) file for the full license text.
diff --git a/README.org b/README.org
deleted file mode 100644
index e131daf..0000000
--- a/README.org
+++ /dev/null
@@ -1,15 +0,0 @@
-* Quality Assurance Settings for museum-digital
-
-Most of the code used at [[https://www.museum-digital.org][museum-digital]] is written in PHP. To keep a uniform code style throughout the code, we use [[https://github.com/squizlabs/PHP_CodeSniffer][PHP Code Sniffer]].
-
-** Tools used
-
-- [[https://github.com/squizlabs/PHP_CodeSniffer][php-codesniffer]]
-- [[https://github.com/phpstan/phpstan][PHPStan - PHP Static Analysis Tool]]
-- [[https://phpunit.de/][phpunit]]
-
-** This Repository
-
-This repository serves to collect generally applicable rules, that can be embedded into the specific rule sets of the different projects.
-
-The file _md_phpcs_rules.xml_ contains the main style guide. When rewriting files to fit the uniform style rules, _md_phpcs_rules_basic.xml_ comes in handy as a first step. It contains the same rules, excluding some which require or encourage a more in-depth look at the code (the prohibition of procedural-style calls to mysqli functions is e.g. a good opportunity to check the efficiency of queries).
diff --git a/rules/md_phpcs_rules.xml b/rules/md_phpcs_rules.xml
index e139381..8010607 100644
--- a/rules/md_phpcs_rules.xml
+++ b/rules/md_phpcs_rules.xml
@@ -13,30 +13,31 @@
     <rule ref='Squiz.Commenting.FunctionComment'/>
     <rule ref='Squiz.Commenting.ClassComment'/>
 
-    <rule ref='SlevomatCodingStandard.PHP.UselessParentheses'/>
+        <!-- <rule ref='SlevomatCodingStandard.PHP.UselessParentheses'/>-->
     <rule ref='SlevomatCodingStandard.PHP.OptimizedFunctionsWithoutUnpacking'/>
     <!-- <rule ref='SlevomatCodingStandard.Variables.DisallowSuperGlobalVariable'/> -->
     <rule ref='SlevomatCodingStandard.Variables.DuplicateAssignmentToVariable'/>
     <!-- <rule ref='SlevomatCodingStandard.Variables.UnusedVariable'/> -->
-        <!-- <rule ref='SlevomatCodingStandard.Variables.UselessVariable'/> -->
+    <rule ref='SlevomatCodingStandard.Variables.UselessVariable'/>
     <rule ref='SlevomatCodingStandard.Arrays.SingleLineArrayWhitespace'/>
     <rule ref='SlevomatCodingStandard.Classes.ConstantSpacing'/>
     <rule ref='SlevomatCodingStandard.PHP.TypeCast'/>
-    <!-- <rule ref='SlevomatCodingStandard.Classes.ClassConstantVisibility'/> -->
+    <rule ref='SlevomatCodingStandard.Classes.ClassConstantVisibility'/>
 
     <rule ref='SlevomatCodingStandard.TypeHints.ParameterTypeHintSpacing'/>
-    <rule ref='SlevomatCodingStandard.TypeHints.PropertyTypeHintSpacing'/>
+    <!-- <rule ref='SlevomatCodingStandard.TypeHints.PropertyTypeHintSpacing'/> -->
 
+    <!--
     <rule ref="SlevomatCodingStandard.Classes.ClassStructure">
         <properties>
             <property name="groups" type="array">
                 <element value="uses"/>
 
-                <!-- Public constants are first but you don't care about the order of protected or private constants -->
+                Public constants are first but you don't care about the order of protected or private constants
                 <element value="public constants"/>
                 <element value="constants"/>
 
-                <!-- You don't care about the order among the properties. The same can be done with "properties" shortcut -->
+                You don't care about the order among the properties. The same can be done with "properties" shortcut 
                 <element value="public static properties, protected static properties, private static properties"/>
                 <element value="public properties, protected properties, private properties"/>
 
@@ -47,6 +48,7 @@
             </property>
         </properties>
     </rule>
+    -->
 
     <!--
     <rule ref='PEAR.ControlStructures.ControlSignature'>
diff --git a/rules/phpstan-rules.neon b/rules/phpstan-rules.neon
index 222d014..cf98e81 100644
--- a/rules/phpstan-rules.neon
+++ b/rules/phpstan-rules.neon
@@ -100,19 +100,11 @@ rules:
     - PHPStan\Rules\VariableVariables\VariableStaticMethodCallRule
     - PHPStan\Rules\VariableVariables\VariableStaticPropertyFetchRule
     - PHPStan\Rules\VariableVariables\VariableVariablesRule
-    - Ergebnis\PHPStan\Rules\Closures\NoNullableReturnTypeDeclarationRule
-    - Ergebnis\PHPStan\Rules\Closures\NoParameterWithNullableTypeDeclarationRule
     - Ergebnis\PHPStan\Rules\Expressions\NoCompactRule
     - Ergebnis\PHPStan\Rules\Expressions\NoErrorSuppressionRule
     - Ergebnis\PHPStan\Rules\Expressions\NoEvalRule
     - Ergebnis\PHPStan\Rules\Files\DeclareStrictTypesRule
-    - Ergebnis\PHPStan\Rules\Functions\NoNullableReturnTypeDeclarationRule
-    - Ergebnis\PHPStan\Rules\Functions\NoParameterWithNullableTypeDeclarationRule
-    - Ergebnis\PHPStan\Rules\Functions\NoParameterWithNullDefaultValueRule
     - Ergebnis\PHPStan\Rules\Methods\FinalInAbstractClassRule
-    - Ergebnis\PHPStan\Rules\Methods\NoNullableReturnTypeDeclarationRule
-    - Ergebnis\PHPStan\Rules\Methods\NoParameterWithNullableTypeDeclarationRule
-    - Ergebnis\PHPStan\Rules\Methods\NoParameterWithNullDefaultValueRule
     - Ergebnis\PHPStan\Rules\Methods\PrivateInFinalClassRule
 
 services:
@@ -147,9 +139,3 @@ services:
         tags:
             - phpstan.rules.rule
 
-    -
-        class: Ergebnis\PHPStan\Rules\Methods\NoParameterWithContainerTypeDeclarationRule
-        arguments:
-            interfacesImplementedByContainers: %ergebnis.interfacesImplementedByContainers%
-        tags:
-            - phpstan.rules.rule