diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index e65dae451a..eed45e0227 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -41,7 +41,7 @@ When you introduce new `public` sniff properties, or your sniff extends a class
 * WordPress-Coding-Standards
 * PHP_CodeSniffer 3.7.2 or higher
 * PHPCSUtils 1.0.8 or higher
-* PHPCSExtra 1.1.0 or higher
+* PHPCSExtra 1.2.0 or higher
 * PHPUnit 4.x, 5.x, 6.x or 7.x
 
 The WordPress Coding Standards use the `PHP_CodeSniffer` native unit test framework for unit testing the sniffs.
diff --git a/WordPress-Core/ruleset.xml b/WordPress-Core/ruleset.xml
index c38349e5c4..5396b02134 100644
--- a/WordPress-Core/ruleset.xml
+++ b/WordPress-Core/ruleset.xml
@@ -869,6 +869,9 @@
 	<!-- Important to prevent issues with content being sent before headers. -->
 	<rule ref="Generic.Files.ByteOrderMark"/>
 
+	<!-- Always have a lowertag PHP open tag. -->
+	<rule ref="Universal.PHP.LowercasePHPTag"/>
+
 	<!-- All line endings should be \n. -->
 	<rule ref="Generic.Files.LineEndings">
 		<properties>
diff --git a/WordPress-Extra/ruleset.xml b/WordPress-Extra/ruleset.xml
index 54c2bd553e..8a104c84ec 100644
--- a/WordPress-Extra/ruleset.xml
+++ b/WordPress-Extra/ruleset.xml
@@ -180,6 +180,9 @@
 	<!-- Detect useless "echo sprintf(...)". -->
 	<rule ref="Universal.CodeAnalysis.NoEchoSprintf"/>
 
+	<!-- Detect use of double negative `!!`. -->
+	<rule ref="Universal.CodeAnalysis.NoDoubleNegative"/>
+
 	<!--
 	#############################################################################
 	Code style sniffs for more recent PHP features and syntaxes.
diff --git a/composer.json b/composer.json
index 4a287cba2e..b6e8abd2f7 100644
--- a/composer.json
+++ b/composer.json
@@ -23,7 +23,7 @@
 		"ext-xmlreader": "*",
 		"squizlabs/php_codesniffer": "^3.7.2",
 		"phpcsstandards/phpcsutils": "^1.0.8",
-		"phpcsstandards/phpcsextra": "^1.1.0"
+		"phpcsstandards/phpcsextra": "^1.2.0"
 	},
 	"require-dev": {
 		"phpcompatibility/php-compatibility": "^9.0",