diff --git a/src/Standards/PSR12/Docs/Operators/OperatorSpacingStandard.xml b/src/Standards/PSR12/Docs/Operators/OperatorSpacingStandard.xml
index 981b1d97a1..dd30c3bd8f 100644
--- a/src/Standards/PSR12/Docs/Operators/OperatorSpacingStandard.xml
+++ b/src/Standards/PSR12/Docs/Operators/OperatorSpacingStandard.xml
@@ -20,6 +20,27 @@ if ($a===$b) {
     $foo=$bar??$a??$b;
 } elseif ($a>$b) {
     $variable=$foo?'foo':'bar';
+}
+        ]]>
+        </code>
+    </code_comparison>
+    <standard>
+    <![CDATA[
+    When the "perCompatible" property is set to "3.0" or higher, the requirement for spaces around the single pipe operator in a multi-catch block is changed to a requirement of "no spaces".
+    ]]>
+    </standard>
+    <code_comparison>
+        <code title="Valid: no spaces around the '|' operator in a multi-catch with 'perCompatible=3.0' (or higher).">
+        <![CDATA[
+try {
+} catch (Exception|RuntimeException $e) {
+}
+        ]]>
+        </code>
+        <code title="Invalid: spaces around the '|' operator in a multi-catch with 'perCompatible=3.0' (or higher).">
+        <![CDATA[
+try {
+} catch (Exception | RuntimeException $e) {
 }
         ]]>
         </code>
diff --git a/src/Standards/PSR12/Sniffs/Operators/OperatorSpacingSniff.php b/src/Standards/PSR12/Sniffs/Operators/OperatorSpacingSniff.php
index 824169438a..898f1a0e8d 100644
--- a/src/Standards/PSR12/Sniffs/Operators/OperatorSpacingSniff.php
+++ b/src/Standards/PSR12/Sniffs/Operators/OperatorSpacingSniff.php
@@ -17,6 +17,13 @@
 class OperatorSpacingSniff extends SquizOperatorSpacingSniff
 {
 
+    /**
+     * The PER version to be compatible with. For backwards compatibility this is set to 1.0 by default.
+     *
+     * @var string
+     */
+    public $perCompatible = '1.0';
+
 
     /**
      * Returns an array of tokens this test wants to listen for.
@@ -75,6 +82,59 @@ public function process(File $phpcsFile, int $stackPtr)
 
         $operator = $tokens[$stackPtr]['content'];
 
+        // PER-CS 3.0: Exception to the rule for pipe operators in multi-catch blocks where no space is required.
+        // As union types didn't exist when PSR-12 was created, the pipe in catch statements
+        // was originally treated as a bitwise operator. This check changes the spacing requirement
+        // for that specific case when opting in to PER-CS 3.0 or higher.
+        if ($tokens[$stackPtr]['code'] === T_BITWISE_OR
+            && isset($tokens[$stackPtr]['nested_parenthesis']) === true
+            && version_compare($this->perCompatible, '3.0', '>=') === true
+        ) {
+            // Calling array_keys() on a nested sub-array can have memory leaks, assign to a variable first.
+            // See https://github.com/squizlabs/PHP_CodeSniffer/pull/2273 .
+            $parenthesis     = $tokens[$stackPtr]['nested_parenthesis'];
+            $parenthesisKeys = array_keys($parenthesis);
+            $bracket         = array_pop($parenthesisKeys);
+            if (isset($tokens[$bracket]['parenthesis_owner']) === true
+                && $tokens[$tokens[$bracket]['parenthesis_owner']]['code'] === T_CATCH
+            ) {
+                if ($tokens[($stackPtr - 1)]['code'] === T_WHITESPACE
+                    && strpos($tokens[($stackPtr - 1)]['content'], $phpcsFile->eolChar) === false
+                    && $tokens[($stackPtr - 1)]['column'] !== 1
+                ) {
+                    $error = 'Expected 0 spaces before "%s" in multi-catch statement; %s found';
+                    $data  = [
+                        $operator,
+                        $tokens[($stackPtr - 1)]['length'],
+                    ];
+
+                    $fix = $phpcsFile->addFixableError($error, $stackPtr, 'MultiCatchSpaceBefore', $data);
+                    if ($fix === true) {
+                        $phpcsFile->fixer->replaceToken(($stackPtr - 1), '');
+                    }
+                }
+
+                if ($tokens[($stackPtr + 1)]['code'] === T_WHITESPACE
+                    && strpos($tokens[($stackPtr + 1)]['content'], $phpcsFile->eolChar) === false
+                ) {
+                    $error = 'Expected 0 spaces after "%s" in multi-catch statement; %s found';
+                    $data  = [
+                        $operator,
+                        $tokens[($stackPtr + 1)]['length'],
+                    ];
+
+                    $fix = $phpcsFile->addFixableError($error, $stackPtr, 'MultiCatchSpaceAfter', $data);
+                    if ($fix === true) {
+                        $phpcsFile->fixer->replaceToken(($stackPtr + 1), '');
+                    }
+                }
+
+                // Now that this special case is handled, we can return early as we don't need to do
+                // further checks.
+                return;
+            }
+        }
+
         $checkBefore = true;
         $checkAfter  = true;
 
diff --git a/src/Standards/PSR12/Tests/Operators/OperatorSpacingUnitTest.1.inc b/src/Standards/PSR12/Tests/Operators/OperatorSpacingUnitTest.1.inc
index 14cf8e9dfd..25e0bd7103 100644
--- a/src/Standards/PSR12/Tests/Operators/OperatorSpacingUnitTest.1.inc
+++ b/src/Standards/PSR12/Tests/Operators/OperatorSpacingUnitTest.1.inc
@@ -77,3 +77,91 @@ function setDefault(#[ImportValue(
     }
 
 declare(strict_types=1);
+
+// Valid.
+try {
+    // nothing
+} catch (Exception | RuntimeException $e) {
+}
+
+// Valid because multiline formatting is undefined.
+try {
+    // nothing
+} catch (
+    Exception
+    | RuntimeException
+    | KlausiException
+    | AnotherException
+    | ItNeverEndsException $e
+) {
+}
+
+// Valid because multiline formatting is undefined.
+try {
+    // nothing
+} catch (
+    Exception |
+    RuntimeException |
+    KlausiException |
+    AnotherException |
+    ItNeverEndsException $e
+) {
+}
+
+// Valid because PSR 12 allows more than one space around operators.
+try {
+    // nothing
+} catch (Exception  |   RuntimeException $e) {
+}
+
+// phpcs:set PSR12.Operators.OperatorSpacing perCompatible 3.0
+
+// Valid.
+try {
+    // nothing
+} catch (Exception|RuntimeException $e) {
+}
+
+// Valid because multiline formatting is undefined.
+try {
+    // nothing
+} catch (
+    Exception
+    |RuntimeException
+    |KlausiException
+    |AnotherException
+    |ItNeverEndsException $e
+) {
+}
+
+// Valid because multiline formatting is undefined.
+try {
+    // nothing
+} catch (
+    Exception|
+    RuntimeException|
+    KlausiException|
+    AnotherException|
+    ItNeverEndsException $e
+) {
+}
+
+// Invalid because of one space.
+try {
+    // nothing
+} catch (Exception | RuntimeException $e) {
+}
+
+// Invalid because of multiple spaces.
+try {
+    // nothing
+} catch (Exception  |   RuntimeException $e) {
+}
+
+// Testing that it works with future versions as well.
+// phpcs:set PSR12.Operators.OperatorSpacing perCompatible 4.0
+
+try {
+    // nothing
+} catch (Exception | RuntimeException $e) {
+}
diff --git a/src/Standards/PSR12/Tests/Operators/OperatorSpacingUnitTest.1.inc.fixed b/src/Standards/PSR12/Tests/Operators/OperatorSpacingUnitTest.1.inc.fixed
index 0f52f1cf74..f780cc6761 100644
--- a/src/Standards/PSR12/Tests/Operators/OperatorSpacingUnitTest.1.inc.fixed
+++ b/src/Standards/PSR12/Tests/Operators/OperatorSpacingUnitTest.1.inc.fixed
@@ -77,3 +77,91 @@ function setDefault(#[ImportValue(
     }
 
 declare(strict_types=1);
+
+// Valid.
+try {
+    // nothing
+} catch (Exception | RuntimeException $e) {
+}
+
+// Valid because multiline formatting is undefined.
+try {
+    // nothing
+} catch (
+    Exception
+    | RuntimeException
+    | KlausiException
+    | AnotherException
+    | ItNeverEndsException $e
+) {
+}
+
+// Valid because multiline formatting is undefined.
+try {
+    // nothing
+} catch (
+    Exception |
+    RuntimeException |
+    KlausiException |
+    AnotherException |
+    ItNeverEndsException $e
+) {
+}
+
+// Valid because PSR 12 allows more than one space around operators.
+try {
+    // nothing
+} catch (Exception  |   RuntimeException $e) {
+}
+
+// phpcs:set PSR12.Operators.OperatorSpacing perCompatible 3.0
+
+// Valid.
+try {
+    // nothing
+} catch (Exception|RuntimeException $e) {
+}
+
+// Valid because multiline formatting is undefined.
+try {
+    // nothing
+} catch (
+    Exception
+    |RuntimeException
+    |KlausiException
+    |AnotherException
+    |ItNeverEndsException $e
+) {
+}
+
+// Valid because multiline formatting is undefined.
+try {
+    // nothing
+} catch (
+    Exception|
+    RuntimeException|
+    KlausiException|
+    AnotherException|
+    ItNeverEndsException $e
+) {
+}
+
+// Invalid because of one space.
+try {
+    // nothing
+} catch (Exception|RuntimeException $e) {
+}
+
+// Invalid because of multiple spaces.
+try {
+    // nothing
+} catch (Exception|RuntimeException $e) {
+}
+
+// Testing that it works with future versions as well.
+// phpcs:set PSR12.Operators.OperatorSpacing perCompatible 4.0
+
+try {
+    // nothing
+} catch (Exception|RuntimeException $e) {
+}
diff --git a/src/Standards/PSR12/Tests/Operators/OperatorSpacingUnitTest.php b/src/Standards/PSR12/Tests/Operators/OperatorSpacingUnitTest.php
index f0643ddcbd..21963420a5 100644
--- a/src/Standards/PSR12/Tests/Operators/OperatorSpacingUnitTest.php
+++ b/src/Standards/PSR12/Tests/Operators/OperatorSpacingUnitTest.php
@@ -36,26 +36,29 @@ public function getErrorList($testFile = '')
         switch ($testFile) {
             case 'OperatorSpacingUnitTest.1.inc':
                 return [
-                    2  => 1,
-                    3  => 2,
-                    4  => 1,
-                    5  => 2,
-                    6  => 4,
-                    9  => 3,
-                    10 => 2,
-                    11 => 3,
-                    13 => 3,
-                    14 => 2,
-                    18 => 1,
-                    20 => 1,
-                    22 => 2,
-                    23 => 2,
-                    26 => 1,
-                    37 => 4,
-                    39 => 1,
-                    40 => 1,
-                    44 => 2,
-                    47 => 2,
+                    2   => 1,
+                    3   => 2,
+                    4   => 1,
+                    5   => 2,
+                    6   => 4,
+                    9   => 3,
+                    10  => 2,
+                    11  => 3,
+                    13  => 3,
+                    14  => 2,
+                    18  => 1,
+                    20  => 1,
+                    22  => 2,
+                    23  => 2,
+                    26  => 1,
+                    37  => 4,
+                    39  => 1,
+                    40  => 1,
+                    44  => 2,
+                    47  => 2,
+                    152 => 2,
+                    158 => 2,
+                    166 => 2,
                 ];
             default:
                 return [];