diff --git a/coder_sniffer/Drupal/Sniffs/NamingConventions/ValidClassNameSniff.php b/coder_sniffer/Drupal/Sniffs/NamingConventions/ValidClassNameSniff.php
index 0ff3a569..82b54d0e 100644
--- a/coder_sniffer/Drupal/Sniffs/NamingConventions/ValidClassNameSniff.php
+++ b/coder_sniffer/Drupal/Sniffs/NamingConventions/ValidClassNameSniff.php
@@ -63,7 +63,7 @@ public function process(File $phpcsFile, $stackPtr)
         // Make sure the first letter is a capital.
         if (preg_match('|^[A-Z]|', $name) === 0) {
             $error = '%s name must use UpperCamel naming and begin with a capital letter';
-            $phpcsFile->addError($error, $stackPtr, 'StartWithCapital', $errorData);
+            $this->processUpperLowerCase($className, $phpcsFile, 'StartWithCapital', $error, $errorData);
         }
 
         // Search for underscores.
@@ -72,16 +72,47 @@ public function process(File $phpcsFile, $stackPtr)
             $phpcsFile->addError($error, $stackPtr, 'NoUnderscores', $errorData);
         }
 
-        // Ensure the name is not all uppercase.
-        // @todo We could make this more strict to check if there are more than
-        // 2 upper case characters in a row anywhere, but not decided yet.
-        // See https://www.drupal.org/project/coder/issues/3497433
-        if (preg_match('|^[A-Z]{3}[^a-z]*$|', $name) === 1) {
+        // Ensure the name does not contain acronyms.
+        if (preg_match('|[A-Z]{3}|', $name) === 1) {
             $error = '%s name must use UpperCamel naming and not contain multiple upper case letters in a row';
-            $phpcsFile->addError($error, $stackPtr, 'NoUpperAcronyms', $errorData);
+            $this->processUpperLowerCase($className, $phpcsFile, 'NoUpperAcronyms', $error, $errorData);
         }
 
     }//end process()
 
 
+    protected function processUpperLowerCase(int $stackPtr, File $phpcsFile, string $errorCode, string $errorMessage, array $errorData): void
+    {
+        $fix = $phpcsFile->addFixableError($errorMessage, $stackPtr, $errorCode, $errorData);
+        if ($fix === false) {
+            return;
+        }
+
+        $tokens = $phpcsFile->getTokens();
+        $name   = ucfirst($tokens[$stackPtr]['content']);
+        $upperCaseStarted = false;
+        for ($i = 0; $i < strlen($name); $i++) {
+            if ($upperCaseStarted === true
+                && ctype_upper($name[$i]) === true
+                && isset($name[($i + 1)])
+                && (ctype_upper($name[($i + 1)]) === true || $name[($i + 1)] === '_')
+            ) {
+                $name[$i] = strtolower($name[$i]);
+            } else {
+                if (ctype_upper($name[$i]) === true) {
+                    $upperCaseStarted = true;
+                } else {
+                    $upperCaseStarted = false;
+                }
+            }
+        }
+
+        $name[(strlen($name) - 1)] = strtolower($name[(strlen($name) - 1)]);
+        $phpcsFile->fixer->replaceToken($stackPtr, $name);
+
+        // @todo Can we move files?
+
+    }//end processUpperLowerCase()
+
+
 }//end class
diff --git a/tests/Drupal/NamingConventions/ValidClassNameUnitTest.inc b/tests/Drupal/NamingConventions/ValidClassNameUnitTest.inc
index dfcf852e..6b5dd4ad 100644
--- a/tests/Drupal/NamingConventions/ValidClassNameUnitTest.inc
+++ b/tests/Drupal/NamingConventions/ValidClassNameUnitTest.inc
@@ -2,24 +2,28 @@
 
 class CorrectClassName {}
 class CorrectClassWithAReallyLongName {}
+class IncorrectJSONClassName {}
 class INCORRECT_CLASS_NAME {}
 class INCORRECTCLASSNAME {}
 class incorrectLowercaseClassName {}
 
 interface CorrectInterfaceName {}
 interface CorrectInterfaceWithAReallyLongName {}
+interface IncorrectJSONInterfaceName {}
 interface INCORRECT_INTERFACE_NAME {}
 interface INCORRECTINTERFACENAME {}
 interface incorrectLowercaseInterfaceName {}
 
 trait CorrectTraitName {}
 trait CorrectTraitWithAReallyLongName {}
+trait IncorrectJSONTraitName {}
 trait INCORRECT_TRAIT_NAME {}
 trait INCORRECTTRAITNAME {}
 trait incorrectLowercaseTraitName {}
 
 enum CorrectEnumName {}
 enum CorrectEnumWithAReallyLongName {}
+enum IncorrectJSONEnumName {}
 enum INCORRECT_ENUM_NAME {}
 enum INCORRECTENUMNAME {}
 enum incorrectLowercaseEnumName {}
diff --git a/tests/Drupal/NamingConventions/ValidClassNameUnitTest.php b/tests/Drupal/NamingConventions/ValidClassNameUnitTest.php
index 37803750..4492d219 100644
--- a/tests/Drupal/NamingConventions/ValidClassNameUnitTest.php
+++ b/tests/Drupal/NamingConventions/ValidClassNameUnitTest.php
@@ -21,18 +21,22 @@ class ValidClassNameUnitTest extends CoderSniffUnitTest
     protected function getErrorList(string $testFile): array
     {
         return [
-            5  => 2,
-            6  => 1,
+            5  => 1,
+            6  => 2,
             7  => 1,
-            11 => 2,
+            8  => 1,
             12 => 1,
-            13 => 1,
-            17 => 2,
-            18 => 1,
+            13 => 2,
+            14 => 1,
+            15 => 1,
             19 => 1,
-            23 => 2,
-            24 => 1,
-            25 => 1,
+            20 => 2,
+            21 => 1,
+            22 => 1,
+            26 => 1,
+            27 => 2,
+            28 => 1,
+            29 => 1,
         ];
 
     }//end getErrorList()
diff --git a/tests/Drupal/NamingConventions/ValidEnumCaseUnitTest.inc b/tests/Drupal/NamingConventions/ValidEnumCaseUnitTest.inc
index d037f5ba..97ee71a4 100644
--- a/tests/Drupal/NamingConventions/ValidEnumCaseUnitTest.inc
+++ b/tests/Drupal/NamingConventions/ValidEnumCaseUnitTest.inc
@@ -7,10 +7,10 @@ enum Test: int {
   case TWO_TEST = 2;
   // Must not contain only upper case.
   case THREE = 3;
-  // Upper case parts are allowed for now.
+  // Upper case parts are not allowed.
   case FourJSONCase = 4;
   case FiveAndAHorseCorrect = 5;
-  case UIExample = 6;
+  case UiExample = 6;
 }
 
 // Those are all ok.
diff --git a/tests/Drupal/NamingConventions/ValidEnumCaseUnitTest.php b/tests/Drupal/NamingConventions/ValidEnumCaseUnitTest.php
index 28a5135b..ee810ff3 100644
--- a/tests/Drupal/NamingConventions/ValidEnumCaseUnitTest.php
+++ b/tests/Drupal/NamingConventions/ValidEnumCaseUnitTest.php
@@ -21,9 +21,10 @@ class ValidEnumCaseUnitTest extends CoderSniffUnitTest
     protected function getErrorList(string $testFile): array
     {
         return [
-            5 => 1,
-            7 => 2,
-            9 => 1,
+            5  => 1,
+            7  => 2,
+            9  => 1,
+            11 => 1,
         ];
 
     }//end getErrorList()