diff --git a/src/Ruleset.php b/src/Ruleset.php
index b6279bf9f3..b87c6be89e 100644
--- a/src/Ruleset.php
+++ b/src/Ruleset.php
@@ -1219,7 +1219,14 @@ private function processRule($rule, $newSniffs, $depth=0)
                             }
 
                             $printValue = rtrim($printValue, ',');
-                        } else {
+                        } else if (isset($prop['value']) === true) {
+                            $message  = 'Passing an array of values to a property using a comma-separated string'.PHP_EOL;
+                            $message .= 'was deprecated in PHP_CodeSniffer 3.3.0. Support will be removed in PHPCS 4.0.0.'.PHP_EOL;
+                            $message .= "The deprecated syntax was used for property \"$name\"".PHP_EOL;
+                            $message .= "for sniff \"$code\".".PHP_EOL;
+                            $message .= 'Pass array values via <element [key="..." ]value="..."> nodes instead.';
+                            $this->msgCache->add($message, MessageCollector::DEPRECATED);
+
                             $value      = (string) $prop['value'];
                             $printValue = $value;
                             if ($value !== '') {
diff --git a/tests/Core/Ruleset/PropertyTypeHandlingTest.php b/tests/Core/Ruleset/PropertyTypeHandlingTest.php
index 346914b142..1db15aa5d2 100644
--- a/tests/Core/Ruleset/PropertyTypeHandlingTest.php
+++ b/tests/Core/Ruleset/PropertyTypeHandlingTest.php
@@ -38,6 +38,35 @@ final class PropertyTypeHandlingTest extends TestCase
     const SNIFF_CLASS = 'Fixtures\\TestStandard\\Sniffs\\SetProperty\\PropertyTypeHandlingSniff';
 
 
+    /**
+     * Verify a deprecation notice is shown when an array property is set from the ruleset using a comma-separated string.
+     *
+     * Support for this format was (soft) deprecated in PHPCS 3.3.0.
+     *
+     * @return void
+     */
+    public function testUsingOldSchoolArrayFormatShowsDeprecationNotice()
+    {
+        $regex  = '`^(';
+        $regex .= 'DEPRECATED: Passing an array of values to a property using a comma-separated string\R';
+        $regex .= 'was deprecated in PHP_CodeSniffer 3\.3\.0\. Support will be removed in PHPCS 4\.0\.0\.\R';
+        $regex .= 'The deprecated syntax was used for property "expectsOldSchool(?:EmptyArray|ArrayWith(?:Extended|Only)?(?:KeysAnd)?Values)"\R';
+        $regex .= 'for sniff "';
+        $regex .= '(?:\./tests/Core/Ruleset/Fixtures/TestStandard/Sniffs/SetProperty/PropertyTypeHandlingSniff\.php|TestStandard\.SetProperty\.PropertyTypeHandling)';
+        $regex .= '"\.\R';
+        $regex .= 'Pass array values via <element \[key="\.\.\." \]value="\.\.\."> nodes instead\.\R';
+        $regex .= '){14}\R$`';
+
+        $this->expectOutputRegex($regex);
+
+        // Set up the ruleset.
+        $standard = __DIR__.'/PropertyTypeHandlingTest.xml';
+        $config   = new ConfigDouble(["--standard=$standard"]);
+        new Ruleset($config);
+
+    }//end testUsingOldSchoolArrayFormatShowsDeprecationNotice()
+
+
     /**
      * Test the value type handling for properties set via a ruleset.
      *
@@ -234,6 +263,9 @@ public static function dataArrayPropertyExtending()
     /**
      * Test Helper.
      *
+     * Note: the deprecations for using comma-separated string to pass an array, are silenced in this helper
+     * as that's not what's being tested here.
+     *
      * @see self::testTypeHandlingWhenSetViaRuleset()
      *
      * @return \PHP_CodeSniffer\Sniffs\Sniff
@@ -245,7 +277,7 @@ private function getSniffObjectForRuleset()
         if (isset($sniffObject) === false) {
             // Set up the ruleset.
             $standard = __DIR__.'/PropertyTypeHandlingTest.xml';
-            $config   = new ConfigDouble(["--standard=$standard"]);
+            $config   = new ConfigDouble(["--standard=$standard", '-q']);
             $ruleset  = new Ruleset($config);
 
             // Verify that our target sniff has been registered.