diff --git a/.github/workflows/install-testing.yml b/.github/workflows/install-testing.yml
index 1599ad019d827..6cd3b70ad7439 100644
--- a/.github/workflows/install-testing.yml
+++ b/.github/workflows/install-testing.yml
@@ -1,6 +1,9 @@
 # Confirms that installing WordPress using WP-CLI works successfully.
 #
 # This workflow is not meant to test wordpress-develop checkouts, but rather tagged versions officially available on WordPress.org.
+#
+# This workflow is triggered for all WordPress versions that are currently receiving security updates. It therefore needs to
+# retain support for older PHP and database versions.
 name: Installation Tests
 
 on:
diff --git a/.github/workflows/local-docker-environment.yml b/.github/workflows/local-docker-environment.yml
index 06638af14a552..5ddb5f5d6fe57 100644
--- a/.github/workflows/local-docker-environment.yml
+++ b/.github/workflows/local-docker-environment.yml
@@ -106,11 +106,6 @@ jobs:
           - db-version: '9.2'
           - db-version: '9.3'
           - db-version: '9.4'
-          # MySQL 9.0+ will not work on PHP 7.2 & 7.3. See https://core.trac.wordpress.org/ticket/61218.
-          - php: '7.2'
-            db-version: '9.5'
-          - php: '7.3'
-            db-version: '9.5'
           # No PHP 8.5 + Memcached support yet.
           - php: '8.5'
             memcached: true
diff --git a/.github/workflows/phpunit-tests.yml b/.github/workflows/phpunit-tests.yml
index 63615dfad19f8..de2de9091677c 100644
--- a/.github/workflows/phpunit-tests.yml
+++ b/.github/workflows/phpunit-tests.yml
@@ -72,7 +72,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ ubuntu-24.04 ]
-        php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4', '8.5' ]
+        php: [ '7.4', '8.0', '8.1', '8.2', '8.3', '8.4', '8.5' ]
         db-type: [ 'mysql' ]
         db-version: [ '5.7', '8.0', '8.4' ]
         tests-domain: [ 'example.org' ]
@@ -149,7 +149,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ ubuntu-24.04 ]
-        php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4', '8.5' ]
+        php: [ '7.4', '8.0', '8.1', '8.2', '8.3', '8.4', '8.5' ]
         db-type: [ 'mariadb' ]
         db-version: [ '5.5', '10.3', '10.5', '10.6', '10.11', '11.4', '11.8' ]
         multisite: [ false, true ]
@@ -201,7 +201,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ ubuntu-24.04 ]
-        php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4', '8.5' ]
+        php: [ '7.4', '8.0', '8.1', '8.2', '8.3', '8.4', '8.5' ]
         db-type: [ 'mysql', 'mariadb' ]
         db-version: [ '9.5', '12.0' ]
         multisite: [ false, true ]
@@ -209,11 +209,6 @@ jobs:
         db-innovation: [ true ]
 
         exclude:
-          # MySQL 9.0+ will not work on PHP <= 7.3 because mysql_native_password was removed. See https://core.trac.wordpress.org/ticket/61218.
-          - php: '7.2'
-            db-version: '9.5'
-          - php: '7.3'
-            db-version: '9.5'
           # Exclude version combinations that don't exist.
           - db-type: 'mariadb'
             db-version: '9.5'
@@ -248,7 +243,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: [ '7.2', '7.4', '8.0', '8.4' ]
+        php: [ '7.4', '8.0', '8.4' ]
         db-type: [ 'mysql' ]
         db-version: [ '8.4' ]
         phpunit-test-groups: [ 'html-api-html5lib-tests' ]
@@ -277,7 +272,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: [ '7.2', '8.4' ]
+        php: [ '7.4', '8.4' ]
         db-version: [ '8.4', '11.8' ]
         db-type: [ 'mysql', 'mariadb' ]
         multisite: [ false ]
diff --git a/.github/workflows/reusable-upgrade-testing.yml b/.github/workflows/reusable-upgrade-testing.yml
index 193802ce9f4ad..aa1760daf6c40 100644
--- a/.github/workflows/reusable-upgrade-testing.yml
+++ b/.github/workflows/reusable-upgrade-testing.yml
@@ -75,8 +75,6 @@ jobs:
           --health-retries="5"
           -e MYSQL_ROOT_PASSWORD="root"
           -e MYSQL_DATABASE="test_db"
-          --entrypoint sh ${{ inputs.db-type }}:${{ inputs.db-version }}
-          -c "exec docker-entrypoint.sh mysqld${{ inputs.db-type == 'mysql' && contains( fromJSON('["7.2", "7.3"]'), inputs.php ) && ' --default-authentication-plugin=mysql_native_password' || '' }}"
 
     steps:
       - name: Set up PHP ${{ inputs.php }}
diff --git a/.github/workflows/upgrade-develop-testing.yml b/.github/workflows/upgrade-develop-testing.yml
index 8d00334c38903..b33188106c44f 100644
--- a/.github/workflows/upgrade-develop-testing.yml
+++ b/.github/workflows/upgrade-develop-testing.yml
@@ -63,20 +63,12 @@ jobs:
       fail-fast: false
       matrix:
         os: [ 'ubuntu-24.04' ]
-        php: [ '7.2', '8.4' ]
+        php: [ '7.4', '8.4' ]
         db-type: [ 'mysql' ]
         db-version: [ '5.7', '8.4' ]
-        # WordPress 4.9 is the oldest version that supports PHP 7.2.
-        wp: [ '4.9', '6.7', '6.8', '6.9-RC1' ]
+        # WordPress 5.3 is the oldest version that supports PHP 7.4.
+        wp: [ '5.3', '6.7', '6.8', '6.9-RC1' ]
         multisite: [ false, true ]
-
-        exclude:
-          # The PHP <= 7.3/MySQL 8.4 jobs currently fail due to mysql_native_password being disabled by default. See https://core.trac.wordpress.org/ticket/61218.
-          - php: '7.2'
-            db-version: '8.4'
-          # WordPress 4.9 does not support PHP 8.4.
-          - php: '8.4'
-            wp: '4.9'
     with:
       os: ${{ matrix.os }}
       php: ${{ matrix.php }}
@@ -98,17 +90,11 @@ jobs:
       fail-fast: false
       matrix:
         os: [ 'ubuntu-24.04' ]
-        php: [ '7.2', '8.4' ]
+        php: [ '7.4', '8.4' ]
         db-type: [ 'mysql' ]
         db-version: [ '8.4' ]
-        # WordPress 4.9 is the oldest version that supports PHP 7.2.
         wp: [ '6.7', '6.8' ]
         multisite: [ false, true ]
-
-        exclude:
-          # The PHP <= 7.3/MySQL 8.4 jobs currently fail due to mysql_native_password being disabled by default. See https://core.trac.wordpress.org/ticket/61218.
-          - php: '7.2'
-            db-version: '8.4'
     with:
       os: ${{ matrix.os }}
       php: ${{ matrix.php }}
diff --git a/.github/workflows/upgrade-testing.yml b/.github/workflows/upgrade-testing.yml
index f6ba23c87a328..4f6025e054580 100644
--- a/.github/workflows/upgrade-testing.yml
+++ b/.github/workflows/upgrade-testing.yml
@@ -68,23 +68,11 @@ jobs:
       fail-fast: false
       matrix:
         os: [ 'ubuntu-24.04' ]
-        php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4', '8.5' ]
+        php: [ '7.4', '8.0', '8.1', '8.2', '8.3', '8.4', '8.5' ]
         db-type: [ 'mysql' ]
         db-version: [ '5.7', '8.0', '8.4', '9.5' ]
         wp: [ '6.7', '6.8' ]
         multisite: [ false, true ]
-
-        exclude:
-          # The PHP <= 7.3/MySQL 8.4 jobs currently fail due to mysql_native_password being disabled by default. See https://core.trac.wordpress.org/ticket/61218.
-          - php: '7.2'
-            db-version: '8.4'
-          - php: '7.3'
-            db-version: '8.4'
-          # MySQL 9.0+ will not work on PHP 7.2 & 7.3. See https://core.trac.wordpress.org/ticket/61218.
-          - php: '7.2'
-            db-version: '9.5'
-          - php: '7.3'
-            db-version: '9.5'
     with:
       os: ${{ matrix.os }}
       php: ${{ matrix.php }}
@@ -105,16 +93,11 @@ jobs:
       fail-fast: false
       matrix:
         os: [ 'ubuntu-24.04' ]
-        php: [ '7.2', '7.4', '8.0', '8.4' ]
+        php: [ '7.4', '8.0', '8.4' ]
         db-type: [ 'mysql' ]
         db-version: [ '5.7', '8.4' ]
         wp: [ '6.0', '6.3', '6.4', '6.5' ]
         multisite: [ false, true ]
-
-        exclude:
-          # The PHP <= 7.3/MySQL 8.4 jobs currently fail due to mysql_native_password being disabled by default. See https://core.trac.wordpress.org/ticket/61218.
-          - php: '7.2'
-            db-version: '8.4'
     with:
       os: ${{ matrix.os }}
       php: ${{ matrix.php }}
@@ -124,7 +107,7 @@ jobs:
       new-version: ${{ inputs.new-version && inputs.new-version || 'latest' }}
       multisite: ${{ matrix.multisite }}
 
-  # Tests 5.x releases where the WordPress database version changed on the oldest and newest supported versions of PHP 7.
+  # Tests 5.x releases where the WordPress database version changed on the only supported version of PHP 7.
   upgrade-tests-wp-5x-php-7x-mysql:
     name: ${{ matrix.wp }} to ${{ inputs.new-version && inputs.new-version || 'latest' }}
     uses: ./.github/workflows/reusable-upgrade-testing.yml
@@ -135,16 +118,11 @@ jobs:
       fail-fast: false
       matrix:
         os: [ 'ubuntu-24.04' ]
-        php: [ '7.2', '7.4' ]
+        php: [ '7.4' ]
         db-type: [ 'mysql' ]
         db-version: [ '5.7', '8.4' ]
         wp: [ '5.0', '5.1', '5.3', '5.4', '5.5', '5.6', '5.9' ]
         multisite: [ false, true ]
-
-        exclude:
-          # The PHP <= 7.3/MySQL 8.4 jobs currently fail due to mysql_native_password being disabled by default. See https://core.trac.wordpress.org/ticket/61218.
-          - php: '7.2'
-            db-version: '8.4'
     with:
       os: ${{ matrix.os }}
       php: ${{ matrix.php }}
@@ -199,23 +177,11 @@ jobs:
       fail-fast: false
       matrix:
         os: [ 'ubuntu-24.04' ]
-        php: [ '7.2', '7.3', '7.4' ]
+        php: [ '7.4' ]
         db-type: [ 'mysql' ]
         db-version: [ '5.7', '8.0', '8.4', '9.5' ]
         wp: [ '4.7' ]
         multisite: [ false, true ]
-
-        exclude:
-          # The PHP <= 7.3/MySQL 8.4 jobs currently fail due to mysql_native_password being disabled by default. See https://core.trac.wordpress.org/ticket/61218.
-          - php: '7.2'
-            db-version: '8.4'
-          - php: '7.3'
-            db-version: '8.4'
-          # MySQL 9.0+ will not work on PHP 7.2 & 7.3. See https://core.trac.wordpress.org/ticket/61218.
-          - php: '7.2'
-            db-version: '9.5'
-          - php: '7.3'
-            db-version: '9.5'
     with:
       os: ${{ matrix.os }}
       php: ${{ matrix.php }}
diff --git a/.version-support-php.json b/.version-support-php.json
index 6618a1680b9bf..5374052d2383c 100644
--- a/.version-support-php.json
+++ b/.version-support-php.json
@@ -1,7 +1,5 @@
 {
 	"7-0": [
-		"7.2",
-		"7.3",
 		"7.4",
 		"8.0",
 		"8.1",
diff --git a/composer.json b/composer.json
index 64ce2356a6719..2c5b20f7879a9 100644
--- a/composer.json
+++ b/composer.json
@@ -13,7 +13,7 @@
 	"require": {
 		"ext-hash": "*",
 		"ext-json": "*",
-		"php": ">=7.2.24"
+		"php": ">=7.4"
 	},
 	"suggest": {
 		"ext-dom": "*"
diff --git a/docker-compose.yml b/docker-compose.yml
index 274e106ec8e5c..cc2ed8d94975e 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -79,9 +79,6 @@ services:
       - ./tools/local-env/mysql-init.sql:/docker-entrypoint-initdb.d/mysql-init.sql
       - mysql:/var/lib/mysql
 
-    # For compatibility with PHP versions that don't support the caching_sha2_password auth plugin used in MySQL 8.0.
-    command: ${LOCAL_DB_AUTH_OPTION-}
-
     healthcheck:
       test: [
         'CMD-SHELL',
diff --git a/phpcompat.xml.dist b/phpcompat.xml.dist
index a4771be79618b..c4ebab64ea19b 100644
--- a/phpcompat.xml.dist
+++ b/phpcompat.xml.dist
@@ -66,8 +66,8 @@
 
 	<rule ref="PHPCompatibilityWP"/>
 
-	<!-- WordPress Core currently supports PHP 7.2+. -->
-	<config name="testVersion" value="7.2-"/>
+	<!-- WordPress Core currently supports PHP 7.4+. -->
+	<config name="testVersion" value="7.4-"/>
 
 	<!--
 	#############################################################################
diff --git a/src/readme.html b/src/readme.html
index 8696b0505a913..c8dd83cdbd9a4 100644
--- a/src/readme.html
+++ b/src/readme.html
@@ -52,7 +52,7 @@ <h2>Migrating from other systems</h2>
 
 <h2>System Requirements</h2>
 <ul>
-	<li><a href="https://www.php.net/">PHP</a> version <strong>7.2.24</strong> or greater.</li>
+	<li><a href="https://www.php.net/">PHP</a> version <strong>7.4</strong> or greater.</li>
 	<li><a href="https://www.mysql.com/">MySQL</a> version <strong>5.5.5</strong> or greater.</li>
 </ul>
 
diff --git a/src/wp-admin/includes/class-wp-site-health.php b/src/wp-admin/includes/class-wp-site-health.php
index 493928677b733..dd537296a8655 100644
--- a/src/wp-admin/includes/class-wp-site-health.php
+++ b/src/wp-admin/includes/class-wp-site-health.php
@@ -965,6 +965,7 @@ public function get_test_php_extensions() {
 				'function' => 'mysqli_connect',
 				'required' => false,
 			),
+			// Sodium was introduced in PHP 7.2, but the extension may not be enabled.
 			'libsodium' => array(
 				'constant'            => 'SODIUM_LIBRARY_VERSION',
 				'required'            => false,
diff --git a/src/wp-admin/includes/misc.php b/src/wp-admin/includes/misc.php
index df95166788394..6c00a0ffb1951 100644
--- a/src/wp-admin/includes/misc.php
+++ b/src/wp-admin/includes/misc.php
@@ -1621,8 +1621,8 @@ function wp_check_php_version() {
 
 	$response['is_lower_than_future_minimum'] = false;
 
-	// The minimum supported PHP version will be updated to 7.4 in the future. Check if the current version is lower.
-	if ( version_compare( $version, '7.4', '<' ) ) {
+	// The minimum supported PHP version will be updated to at least 8.0 in the future. Check if the current version is lower.
+	if ( version_compare( $version, '8.0', '<' ) ) {
 		$response['is_lower_than_future_minimum'] = true;
 
 		// Force showing of warnings.
diff --git a/src/wp-includes/compat.php b/src/wp-includes/compat.php
index af733c830dbc2..3ac1372fdca1e 100644
--- a/src/wp-includes/compat.php
+++ b/src/wp-includes/compat.php
@@ -296,80 +296,11 @@ function utf8_decode( $utf8_text ): string {
 	endif;
 endif;
 
-// sodium_crypto_box() was introduced in PHP 7.2.
+// sodium_crypto_box() was introduced with Sodium in PHP 7.2, but the extension may not be enabled.
 if ( ! function_exists( 'sodium_crypto_box' ) ) {
 	require ABSPATH . WPINC . '/sodium_compat/autoload.php';
 }
 
-if ( ! function_exists( 'is_countable' ) ) {
-	/**
-	 * Polyfill for is_countable() function added in PHP 7.3.
-	 *
-	 * Verify that the content of a variable is an array or an object
-	 * implementing the Countable interface.
-	 *
-	 * @since 4.9.6
-	 *
-	 * @param mixed $value The value to check.
-	 * @return bool True if `$value` is countable, false otherwise.
-	 */
-	function is_countable( $value ) {
-		return ( is_array( $value )
-			|| $value instanceof Countable
-			|| $value instanceof SimpleXMLElement
-			|| $value instanceof ResourceBundle
-		);
-	}
-}
-
-if ( ! function_exists( 'array_key_first' ) ) {
-	/**
-	 * Polyfill for array_key_first() function added in PHP 7.3.
-	 *
-	 * Get the first key of the given array without affecting
-	 * the internal array pointer.
-	 *
-	 * @since 5.9.0
-	 *
-	 * @param array $array An array.
-	 * @return string|int|null The first key of array if the array
-	 *                         is not empty; `null` otherwise.
-	 */
-	function array_key_first( array $array ) { // phpcs:ignore Universal.NamingConventions.NoReservedKeywordParameterNames.arrayFound
-		if ( empty( $array ) ) {
-			return null;
-		}
-
-		foreach ( $array as $key => $value ) {
-			return $key;
-		}
-	}
-}
-
-if ( ! function_exists( 'array_key_last' ) ) {
-	/**
-	 * Polyfill for `array_key_last()` function added in PHP 7.3.
-	 *
-	 * Get the last key of the given array without affecting the
-	 * internal array pointer.
-	 *
-	 * @since 5.9.0
-	 *
-	 * @param array $array An array.
-	 * @return string|int|null The last key of array if the array
-	 *.                        is not empty; `null` otherwise.
-	 */
-	function array_key_last( array $array ) { // phpcs:ignore Universal.NamingConventions.NoReservedKeywordParameterNames.arrayFound
-		if ( empty( $array ) ) {
-			return null;
-		}
-
-		end( $array );
-
-		return key( $array );
-	}
-}
-
 if ( ! function_exists( 'array_is_list' ) ) {
 	/**
 	 * Polyfill for `array_is_list()` function added in PHP 8.1.
diff --git a/src/wp-includes/pluggable.php b/src/wp-includes/pluggable.php
index 99c23540d8983..4bb8e870cab2e 100644
--- a/src/wp-includes/pluggable.php
+++ b/src/wp-includes/pluggable.php
@@ -2777,11 +2777,10 @@ function wp_hash_password(
 		 * - `PASSWORD_ARGON2ID`
 		 * - `PASSWORD_DEFAULT`
 		 *
-		 * The values of the algorithm constants are strings in PHP 7.4+ and integers in PHP 7.3 and earlier.
-		 *
 		 * @since 6.8.0
+		 * @since 7.0.0 The `$algorithm` parameter is now always a string.
 		 *
-		 * @param string|int $algorithm The hashing algorithm. Default is the value of the `PASSWORD_BCRYPT` constant.
+		 * @param string $algorithm The hashing algorithm. Default is the value of the `PASSWORD_BCRYPT` constant.
 		 */
 		$algorithm = apply_filters( 'wp_hash_password_algorithm', PASSWORD_BCRYPT );
 
@@ -2791,14 +2790,13 @@ function wp_hash_password(
 		 * The default hashing algorithm is bcrypt, but this can be changed via the {@see 'wp_hash_password_algorithm'}
 		 * filter. You must ensure that the options are appropriate for the algorithm in use.
 		 *
-		 * The values of the algorithm constants are strings in PHP 7.4+ and integers in PHP 7.3 and earlier.
-		 *
 		 * @since 6.8.0
+		 * @since 7.0.0 The `$algorithm` parameter is now always a string.
 		 *
-		 * @param array      $options   Array of options to pass to the password hashing functions.
-		 *                              By default this is an empty array which means the default
-		 *                              options will be used.
-		 * @param string|int $algorithm The hashing algorithm in use.
+		 * @param array  $options   Array of options to pass to the password hashing functions.
+		 *                          By default this is an empty array which means the default
+		 *                          options will be used.
+		 * @param string $algorithm The hashing algorithm in use.
 		 */
 		$options = apply_filters( 'wp_hash_password_options', array(), $algorithm );
 
diff --git a/src/wp-includes/version.php b/src/wp-includes/version.php
index fb46afd6789c5..f1d2d950ab737 100644
--- a/src/wp-includes/version.php
+++ b/src/wp-includes/version.php
@@ -37,7 +37,7 @@
  *
  * @global string $required_php_version
  */
-$required_php_version = '7.2.24';
+$required_php_version = '7.4';
 
 /**
  * Holds the names of required PHP extensions.
diff --git a/tests/phpunit/includes/abstract-testcase.php b/tests/phpunit/includes/abstract-testcase.php
index 35bf18f688feb..d83b23ca4cf5c 100644
--- a/tests/phpunit/includes/abstract-testcase.php
+++ b/tests/phpunit/includes/abstract-testcase.php
@@ -142,10 +142,10 @@ public function set_up() {
 	/**
 	 * Sets the bcrypt cost option for password hashing during tests.
 	 *
-	 * @param array      $options   The options for password hashing.
-	 * @param string|int $algorithm The algorithm to use for hashing. This is a string in PHP 7.4+ and an integer in PHP 7.3 and earlier.
+	 * @param array  $options   The options for password hashing.
+	 * @param string $algorithm The algorithm to use for hashing.
 	 */
-	public function wp_hash_password_options( array $options, $algorithm ): array {
+	public function wp_hash_password_options( array $options, string $algorithm ): array {
 		if ( PASSWORD_BCRYPT === $algorithm ) {
 			$options['cost'] = 5;
 		}
@@ -1595,14 +1595,6 @@ public function scandir( $dir ) {
 			}
 		}
 
-		/*
-		 * Compatibility check for PHP < 7.4, where array_merge() expects at least one array.
-		 * See: https://3v4l.org/BIQMA
-		 */
-		if ( array() === $matched_dirs ) {
-			return array();
-		}
-
 		return array_merge( ...$matched_dirs );
 	}
 
diff --git a/tests/phpunit/tests/admin/wpMediaListTable.php b/tests/phpunit/tests/admin/wpMediaListTable.php
index b6af6b660cba2..31d2bfa7cbb9d 100644
--- a/tests/phpunit/tests/admin/wpMediaListTable.php
+++ b/tests/phpunit/tests/admin/wpMediaListTable.php
@@ -122,7 +122,7 @@ public function tear_down() {
 	 * does not result in a PHP warning.
 	 *
 	 * The warning that we should not see:
-	 * PHP <= 7.4: `Invalid argument supplied for foreach()`.
+	 * PHP 7.4: `Invalid argument supplied for foreach()`.
 	 * PHP 8.0 and higher: `Warning: foreach() argument must be of type array|object, bool given`.
 	 *
 	 * Note: This does not test the actual functioning of the WP_Media_List_Table::prepare_items() method.
diff --git a/tests/phpunit/tests/compat/arrayKeyFirst.php b/tests/phpunit/tests/compat/arrayKeyFirst.php
deleted file mode 100644
index 28db82e363a6a..0000000000000
--- a/tests/phpunit/tests/compat/arrayKeyFirst.php
+++ /dev/null
@@ -1,68 +0,0 @@
-<?php
-
-/**
- * @group compat
- *
- * @covers ::array_key_first
- */
-class Tests_Compat_arrayKeyFirst extends WP_UnitTestCase {
-
-	/**
-	 * Test that array_key_first() is always available (either from PHP or WP).
-	 * @ticket 45055
-	 */
-	public function test_array_key_first_availability() {
-		$this->assertTrue( function_exists( 'array_key_first' ) );
-	}
-
-	/**
-	 * @dataProvider data_array_key_first
-	 *
-	 * @ticket 45055
-	 *
-	 * @param bool $expected The value of the key extracted to extracted from given array.
-	 * @param array $arr     The array to get first key from.
-	 */
-	public function test_array_key_first( $expected, $arr ) {
-		$this->assertSame( $expected, array_key_first( $arr ) );
-	}
-
-	/**
-	 * Data provider.
-	 *
-	 * @return array[]
-	 */
-	public function data_array_key_first() {
-		return array(
-			'string key'  => array(
-				'expected' => 'key1',
-				'arr'      => array(
-					'key1' => 'val1',
-					'key2' => 'val2',
-				),
-			),
-			'int key'     => array(
-				'expected' => 99,
-				'arr'      => array(
-					99 => 'val1',
-					1  => 'val2',
-				),
-			),
-			'no key'      => array(
-				'expected' => 0,
-				'arr'      => array( 'val1', 'val2' ),
-			),
-			'multi array' => array(
-				'expected' => 99,
-				'arr'      => array(
-					99 => array( 22 => 'val1' ),
-					1  => 'val2',
-				),
-			),
-			'empty array' => array(
-				'expected' => null,
-				'arr'      => array(),
-			),
-		);
-	}
-}
diff --git a/tests/phpunit/tests/compat/arrayKeyLast.php b/tests/phpunit/tests/compat/arrayKeyLast.php
deleted file mode 100644
index 819e850f13769..0000000000000
--- a/tests/phpunit/tests/compat/arrayKeyLast.php
+++ /dev/null
@@ -1,77 +0,0 @@
-<?php
-
-/**
- * @group compat
- *
- * @covers ::array_key_last
- */
-class Tests_Compat_ArrayKeyLast extends WP_UnitTestCase {
-
-	/**
-	 * Test that array_key_last() is always available (either from PHP or WP).
-	 *
-	 * @ticket 45055
-	 */
-	public function test_array_key_last_availability() {
-		$this->assertTrue( function_exists( 'array_key_last' ) );
-	}
-
-	/**
-	 * @dataProvider data_array_key_last
-	 *
-	 * @ticket 45055
-	 *
-	 * @param bool  $expected The value of the key extracted to extracted from given array.
-	 * @param array $arr      The array to get last key from.
-	 */
-	public function test_array_key_last( $expected, $arr ) {
-		$this->assertSame( $expected, array_key_last( $arr ) );
-	}
-
-	/**
-	 * Data provider for test_array_key_last().
-	 *
-	 * @return array
-	 */
-	public function data_array_key_last() {
-		return array(
-			'string key'  => array(
-				'expected' => 'key2',
-				'arr'      => array(
-					'key1' => 'val1',
-					'key2' => 'val2',
-				),
-			),
-			'int key'     => array(
-				'expected' => 1,
-				'arr'      => array(
-					99 => 'val1',
-					1  => 'val2',
-				),
-			),
-			'no key'      => array(
-				'expected' => 1,
-				'arr'      => array( 'val1', 'val2' ),
-			),
-			'multi array' => array(
-				'expected' => 1,
-				'arr'      => array(
-					99 => array( 22 => 'val1' ),
-					1  => 'val2',
-				),
-			),
-			'mixed keys'  => array(
-				'expected' => 1,
-				'arr'      => array(
-					'val1',
-					'key2' => 'val2',
-					'val3',
-				),
-			),
-			'empty array' => array(
-				'expected' => null,
-				'arr'      => array(),
-			),
-		);
-	}
-}
diff --git a/tests/phpunit/tests/compat/isCountable.php b/tests/phpunit/tests/compat/isCountable.php
deleted file mode 100644
index 66bf3c8c6c09f..0000000000000
--- a/tests/phpunit/tests/compat/isCountable.php
+++ /dev/null
@@ -1,117 +0,0 @@
-<?php
-
-/**
- * @group compat
- *
- * @covers ::is_countable
- */
-class Tests_Compat_isCountable extends WP_UnitTestCase {
-
-	/**
-	 * Test that is_countable() is always available (either from PHP or WP).
-	 *
-	 * @ticket 43583
-	 */
-	public function test_is_countable_availability() {
-		$this->assertTrue( function_exists( 'is_countable' ) );
-	}
-
-	/**
-	 * Test is_countable() polyfill.
-	 *
-	 * @ticket 43583
-	 *
-	 * @dataProvider data_is_countable_functionality
-	 *
-	 * @param mixed $variable     Variable to check.
-	 * @param bool  $is_countable The expected return value of PHP 7.3 is_countable() function.
-	 */
-	public function test_is_countable_functionality( $variable, $is_countable ) {
-		$this->assertSame( $is_countable, is_countable( $variable ) );
-	}
-
-	/**
-	 * Data provider for test_is_countable_functionality().
-	 *
-	 * @ticket 43583
-	 *
-	 * @return array {
-	 *     @type array {
-	 *         @type mixed $variable     Variable to check.
-	 *         @type bool  $is_countable The expected return value of PHP 7.3 is_countable() function.
-	 *     }
-	 * }
-	 */
-	public function data_is_countable_functionality() {
-		return array(
-			'boolean true'                     => array(
-				'variable'     => true,
-				'is_countable' => false,
-			),
-			'plain stdClass object'            => array(
-				'variable'     => new stdClass(),
-				'is_countable' => false,
-			),
-			'Array iterator object'            => array(
-				'variable'     => new ArrayIteratorFakeForIsCountable(),
-				'is_countable' => true,
-			),
-			'Countable object'                 => array(
-				'variable'     => new CountableFakeForIsCountable(),
-				'is_countable' => true,
-			),
-			'integer 16'                       => array(
-				'variable'     => 16,
-				'is_countable' => false,
-			),
-			'null'                             => array(
-				'variable'     => null,
-				'is_countable' => false,
-			),
-			'non-empty array, 3 items'         => array(
-				'variable'     => array( 1, 2, 3 ),
-				'is_countable' => true,
-			),
-			'non-empty array, 1 item via cast' => array(
-				'variable'     => (array) 1,
-				'is_countable' => true,
-			),
-			'array cast to object'             => array(
-				'variable'     => (object) array( 'foo', 'bar', 'baz' ),
-				'is_countable' => false,
-			),
-		);
-	}
-
-	/**
-	 * Test is_countable() polyfill for ResourceBundle.
-	 *
-	 * @ticket 43583
-	 *
-	 * @requires extension intl
-	 */
-	public function test_is_countable_ResourceBundle() {
-		$this->assertTrue( is_countable( new ResourceBundle( 'en', null ) ) );
-	}
-
-	/**
-	 * Test is_countable() polyfill for SimpleXMLElement.
-	 *
-	 * @ticket 43583
-	 *
-	 * @requires extension simplexml
-	 */
-	public function test_is_countable_SimpleXMLElement() {
-		$this->assertTrue( is_countable( new SimpleXMLElement( '<xml><tag>1</tag><tag>2</tag></xml>' ) ) );
-	}
-}
-
-class ArrayIteratorFakeForIsCountable extends ArrayIterator {
-}
-
-class CountableFakeForIsCountable implements Countable {
-	#[ReturnTypeWillChange]
-	public function count() {
-		return 16;
-	}
-}
diff --git a/tools/local-env/mysql-old-php.conf b/tools/local-env/mysql-old-php.conf
deleted file mode 100644
index ae1cb9b72a7f5..0000000000000
--- a/tools/local-env/mysql-old-php.conf
+++ /dev/null
@@ -1,20 +0,0 @@
-##
-# The local Docker environment will try to use the database software's default authentication plugin whenever possible.
-#
-# One exception to this is using PHP 7.2 & 7.3 in combination with MySQL >= 8.0. These versions of PHP lack support for
-# MySQL's caching_sha2_password plugin, which was made the new default in MySQL 8.0.
-#
-# Until MySQL 8.4, this could easily be changed using the --default-authentication-plugin with the old value of
-# mysql_native_password.
-#
-# In MySQL 8.4, the  --default-authentication-plugin option was removed in favor of --authentication-policy and
-# mysql_native_password was disabled by default.
-#
-# When mounted to the database container in the local Docker environment, this file turns the old authentication plugin
-# back on so that PHP 7.2 & 7.3 can be used in combination with MySQL 8.4.
-#
-# MySQL 9.0 will remove mysql_native_password.
-##
-
-[mysqld]
-mysql-native-password=ON
diff --git a/tools/local-env/old-php-mysql-84.override.yml b/tools/local-env/old-php-mysql-84.override.yml
deleted file mode 100644
index 3eca65f3c1c0e..0000000000000
--- a/tools/local-env/old-php-mysql-84.override.yml
+++ /dev/null
@@ -1,5 +0,0 @@
-services:
-
-  mysql:
-    volumes:
-      - ./tools/local-env/mysql-old-php.conf:/etc/mysql/conf.d/config-file.cnf
diff --git a/tools/local-env/scripts/install.js b/tools/local-env/scripts/install.js
index 44b9d1596a7ee..80b5c7eb19836 100644
--- a/tools/local-env/scripts/install.js
+++ b/tools/local-env/scripts/install.js
@@ -9,9 +9,6 @@ const local_env_utils = require( './utils' );
 
 dotenvExpand.expand( dotenv.config() );
 
-// Determine if a non-default database authentication plugin needs to be used.
-local_env_utils.determine_auth_option();
-
 // Create wp-config.php.
 wp_cli( `config create --dbname=wordpress_develop --dbuser=root --dbpass=password --dbhost=mysql --force --config-file="wp-config.php"` );
 
diff --git a/tools/local-env/scripts/start.js b/tools/local-env/scripts/start.js
index b0389b2fb0a7f..66559d4c10b85 100644
--- a/tools/local-env/scripts/start.js
+++ b/tools/local-env/scripts/start.js
@@ -15,9 +15,6 @@ dotenvExpand.expand( dotenv.config() );
 
 const composeFiles = local_env_utils.get_compose_files();
 
-// Determine if a non-default database authentication plugin needs to be used.
-local_env_utils.determine_auth_option();
-
 // Check if the Docker service is running.
 try {
 	execSync( 'docker info' );
diff --git a/tools/local-env/scripts/utils.js b/tools/local-env/scripts/utils.js
index 3f3e601db2287..51f02e32a1d2d 100644
--- a/tools/local-env/scripts/utils.js
+++ b/tools/local-env/scripts/utils.js
@@ -10,9 +10,6 @@ const local_env_utils = {
 	 *
 	 * By default, only the standard docker-compose.yml file will be used.
 	 *
-	 * When PHP 7.2 or 7.3 is used in combination with MySQL 8.4, an override file will also be returned to ensure
-	 * that the mysql_native_password plugin authentication plugin is on and available for use.
-	 *
 	 * @return {string[]} Compose files.
 	 */
 	get_compose_files: function() {
@@ -22,41 +19,7 @@ const local_env_utils = {
 			composeFiles.push( 'docker-compose.override.yml' );
 		}
 
-		if ( process.env.LOCAL_DB_TYPE !== 'mysql' ) {
-			return composeFiles;
-		}
-
-		if ( process.env.LOCAL_PHP !== '7.2-fpm' && process.env.LOCAL_PHP !== '7.3-fpm' ) {
-			return composeFiles;
-		}
-
-		// PHP 7.2/7.3 in combination with MySQL 8.4 requires additional configuration to function properly.
-		if ( process.env.LOCAL_DB_VERSION === '8.4' ) {
-			composeFiles.push( 'tools/local-env/old-php-mysql-84.override.yml' );
-		}
-
 		return composeFiles;
-	},
-
-	/**
-	 * Determines the option to pass for proper authentication plugin configuration given the specified PHP version,
-	 * database type, and database version.
-	 */
-	determine_auth_option: function() {
-		if ( process.env.LOCAL_DB_TYPE !== 'mysql' ) {
-			return;
-		}
-
-		if ( process.env.LOCAL_PHP !== '7.2-fpm' && process.env.LOCAL_PHP !== '7.3-fpm' ) {
-			return;
-		}
-
-		// MySQL 8.4 removed --default-authentication-plugin in favor of --authentication-policy.
-		if ( process.env.LOCAL_DB_VERSION === '8.4' ) {
-			process.env.LOCAL_DB_AUTH_OPTION = '--authentication-policy=mysql_native_password';
-		} else {
-			process.env.LOCAL_DB_AUTH_OPTION = '--default-authentication-plugin=mysql_native_password';
-		}
 	}
 };