diff --git a/Magento2/Sniffs/Classes/DiscouragedDependenciesSniff.php b/Magento2/Sniffs/Classes/DiscouragedDependenciesSniff.php
index f5e45c63..fbaad301 100644
--- a/Magento2/Sniffs/Classes/DiscouragedDependenciesSniff.php
+++ b/Magento2/Sniffs/Classes/DiscouragedDependenciesSniff.php
@@ -15,7 +15,7 @@
  */
 class DiscouragedDependenciesSniff implements Sniff
 {
-    const CONSTRUCT_METHOD_NAME = '__construct';
+    private const CONSTRUCT_METHOD_NAME = '__construct';
 
     /**
      * String representation of warning.
diff --git a/Magento2/Sniffs/Html/HtmlDirectiveSniff.php b/Magento2/Sniffs/Html/HtmlDirectiveSniff.php
index d140f96c..2fdc0518 100644
--- a/Magento2/Sniffs/Html/HtmlDirectiveSniff.php
+++ b/Magento2/Sniffs/Html/HtmlDirectiveSniff.php
@@ -16,10 +16,10 @@
  */
 class HtmlDirectiveSniff implements Sniff
 {
-    const CONSTRUCTION_DEPEND_PATTERN = '/{{depend\s*(.*?)}}(.*?){{\\/depend\s*}}/si';
-    const CONSTRUCTION_IF_PATTERN = '/{{if\s*(.*?)}}(.*?)({{else}}(.*?))?{{\\/if\s*}}/si';
-    const LOOP_PATTERN = '/{{for(?P<loopItem>.*? )(in)(?P<loopData>.*?)}}(?P<loopBody>.*?){{\/for}}/si';
-    const CONSTRUCTION_PATTERN = '/{{([a-z]{0,10})(.*?)}}(?:(.*?)(?:{{\/(?:\\1)}}))?/si';
+    private const CONSTRUCTION_DEPEND_PATTERN = '/{{depend\s*(.*?)}}(.*?){{\\/depend\s*}}/si';
+    private const CONSTRUCTION_IF_PATTERN = '/{{if\s*(.*?)}}(.*?)({{else}}(.*?))?{{\\/if\s*}}/si';
+    private const LOOP_PATTERN = '/{{for(?P<loopItem>.*? )(in)(?P<loopData>.*?)}}(?P<loopBody>.*?){{\/for}}/si';
+    private const CONSTRUCTION_PATTERN = '/{{([a-z]{0,10})(.*?)}}(?:(.*?)(?:{{\/(?:\\1)}}))?/si';
 
     /**
      * @var array
diff --git a/Magento2/Sniffs/Less/CommentLevelsSniff.php b/Magento2/Sniffs/Less/CommentLevelsSniff.php
index e192f659..be7c93c9 100644
--- a/Magento2/Sniffs/Less/CommentLevelsSniff.php
+++ b/Magento2/Sniffs/Less/CommentLevelsSniff.php
@@ -19,11 +19,11 @@
  */
 class CommentLevelsSniff implements Sniff
 {
-    const COMMENT_STRING = '//';
+    private const COMMENT_STRING = '//';
 
-    const FIRST_LEVEL_COMMENT = '_____________________________________________';
+    private const FIRST_LEVEL_COMMENT = '_____________________________________________';
 
-    const SECOND_LEVEL_COMMENT = '--';
+    private const SECOND_LEVEL_COMMENT = '--';
 
     /**
      * @var array
diff --git a/Magento2/Sniffs/Less/TokenizerSymbolsInterface.php b/Magento2/Sniffs/Less/TokenizerSymbolsInterface.php
index da690f79..c640e27a 100644
--- a/Magento2/Sniffs/Less/TokenizerSymbolsInterface.php
+++ b/Magento2/Sniffs/Less/TokenizerSymbolsInterface.php
@@ -10,18 +10,18 @@
  */
 interface TokenizerSymbolsInterface
 {
-    const TOKENIZER_CSS = 'CSS';
+    public const TOKENIZER_CSS = 'CSS';
 
     /**#@+
      * Symbols for usage into Sniffers
      */
-    const BITWISE_AND         = '&';
-    const COLON               = ';';
-    const OPEN_PARENTHESIS    = '(';
-    const CLOSE_PARENTHESIS   = ')';
-    const NEW_LINE            = "\n";
-    const WHITESPACE          = ' ';
-    const DOUBLE_WHITESPACE   = '  ';
-    const INDENT_SPACES       = '    ';
+    public const BITWISE_AND         = '&';
+    public const COLON               = ';';
+    public const OPEN_PARENTHESIS    = '(';
+    public const CLOSE_PARENTHESIS   = ')';
+    public const NEW_LINE            = "\n";
+    public const WHITESPACE          = ' ';
+    public const DOUBLE_WHITESPACE   = '  ';
+    public const INDENT_SPACES       = '    ';
     /**#@-*/
 }
diff --git a/Magento2/Sniffs/Less/ZeroUnitsSniff.php b/Magento2/Sniffs/Less/ZeroUnitsSniff.php
index 5b8851fa..7117bdb8 100644
--- a/Magento2/Sniffs/Less/ZeroUnitsSniff.php
+++ b/Magento2/Sniffs/Less/ZeroUnitsSniff.php
@@ -19,9 +19,9 @@
  */
 class ZeroUnitsSniff implements Sniff
 {
-    const CSS_PROPERTY_UNIT_PX = 'px';
-    const CSS_PROPERTY_UNIT_EM = 'em';
-    const CSS_PROPERTY_UNIT_REM = 'rem';
+    private const CSS_PROPERTY_UNIT_PX = 'px';
+    private const CSS_PROPERTY_UNIT_EM = 'em';
+    private const CSS_PROPERTY_UNIT_REM = 'rem';
 
     /**
      * @var array
diff --git a/Magento2/Sniffs/Methods/DeprecatedModelMethodSniff.php b/Magento2/Sniffs/Methods/DeprecatedModelMethodSniff.php
index f094c353..41a9f97b 100644
--- a/Magento2/Sniffs/Methods/DeprecatedModelMethodSniff.php
+++ b/Magento2/Sniffs/Methods/DeprecatedModelMethodSniff.php
@@ -13,7 +13,7 @@
  */
 class DeprecatedModelMethodSniff implements Sniff
 {
-    const RESOURCE_METHOD = "getResource";
+    private const RESOURCE_METHOD = "getResource";
 
     /**
      * String representation of warning.
diff --git a/Magento2/ruleset.xml b/Magento2/ruleset.xml
index c35d5a9b..97d40604 100644
--- a/Magento2/ruleset.xml
+++ b/Magento2/ruleset.xml
@@ -696,6 +696,10 @@
     <rule ref="Squiz.WhiteSpace.SuperfluousWhitespace.EmptyLines">
         <severity>0</severity>
     </rule>
+    <rule ref="PSR12.Properties.ConstantVisibility">
+        <severity>6</severity>
+        <type>warning</type>
+    </rule>
 
     <!-- Severity 5 warnings: PHPDoc formatting and commenting issues. -->
     <rule ref="Magento2.Commenting.ClassAndInterfacePHPDocFormatting">