diff --git a/bin/plugin/commands/readme.js b/bin/plugin/commands/readme.js
index 12f44b0df9..8b4cd0d3fb 100644
--- a/bin/plugin/commands/readme.js
+++ b/bin/plugin/commands/readme.js
@@ -15,6 +15,7 @@ const { getChangelog } = require( './changelog' );
  * @typedef WPReadmeCommandOptions
  *
  * @property {string=} milestone Optional milestone title, to update the changelog in the readme.
+ * @property {string=} path      Optional path to the readme.txt file to update. If omitted, it will be detected via --milestone.
  * @property {string=} token     Optional personal GitHub access token, only relevant for changelog updates.
  */
 
@@ -24,6 +25,7 @@ const { getChangelog } = require( './changelog' );
  * @property {string}  owner     GitHub repository owner.
  * @property {string}  repo      GitHub repository name.
  * @property {string=} milestone Optional milestone title, to update the changelog in the readme.
+ * @property {string=} path      Optional path to the readme.txt file to update.
  * @property {string=} token     Optional personal GitHub access token, only relevant for changelog updates.
  */
 
@@ -32,6 +34,11 @@ exports.options = [
 		argname: '-m, --milestone <milestone>',
 		description: 'Milestone title, to update the changelog',
 	},
+	{
+		argname: '-p, --path <path>',
+		description:
+			'Path to the readme.txt file to update; if omitted, it will be detected via --milestone',
+	},
 	{
 		argname: '-t, --token <token>',
 		description: 'GitHub token',
@@ -48,10 +55,37 @@ exports.handler = async ( opt ) => {
 		owner: config.githubRepositoryOwner,
 		repo: config.githubRepositoryName,
 		milestone: opt.milestone,
+		path: opt.path,
 		token: opt.token,
 	} );
 };
 
+/**
+ * Detects the path to the readme.txt file to update based on the milestone title.
+ *
+ * @param {string} milestone Milestone title.
+ *
+ * @return {string} Detected readme.txt path.
+ */
+function detectReadmePath( milestone ) {
+	const slug = milestone.match( /^([a-z0-9-]+) / );
+	if ( ! slug ) {
+		throw new Error(
+			`The ${ milestone } milestone does not start with a valid plugin slug.`
+		);
+	}
+
+	if ( 'performance-lab' === slug[ 1 ] ) {
+		return 'readme.txt';
+	}
+
+	if ( ! fs.existsSync( path.join( '.', `plugins/${ slug[ 1 ] }` ) ) ) {
+		throw new Error( `Unknown plugin with slug '${ slug[ 1 ] }'` );
+	}
+
+	return `plugins/${ slug[ 1 ] }/readme.txt`;
+}
+
 /**
  * Updates the `readme.txt` file with the given changelog.
  *
@@ -59,9 +93,19 @@ exports.handler = async ( opt ) => {
  * @param {WPReadmeSettings} settings  Readme settings.
  */
 function updateReadmeChangelog( changelog, settings ) {
-	const regex = new RegExp( `= ${ settings.milestone } =[^=]+` );
+	// Detect the version number to replace it in readme changelog, if already present.
+	const version = settings.milestone.match(
+		/\d+\.\d+(\.\d+)?(-[A-Za-z0-9.]+)?$/
+	);
+	if ( ! version ) {
+		throw new Error(
+			`The ${ settings.milestone } milestone does not end with a version number.`
+		);
+	}
 
-	const readmeFile = path.join( '.', 'readme.txt' );
+	const regex = new RegExp( `= ${ version[ 0 ] } =[^=]+` );
+
+	const readmeFile = path.join( '.', settings.path );
 	const fileContent = fs.readFileSync( readmeFile, 'utf8' );
 
 	let newContent;
@@ -95,6 +139,10 @@ async function updateReadme( settings ) {
 		);
 
 		try {
+			if ( ! settings.path ) {
+				settings.path = detectReadmePath( settings.milestone );
+			}
+
 			const changelog = await getChangelog( {
 				owner: settings.owner,
 				repo: settings.repo,
@@ -108,6 +156,8 @@ async function updateReadme( settings ) {
 				return;
 			}
 		}
-		log( formats.success( `\n💃readme.txt successfully updated\n\n` ) );
+		log(
+			formats.success( `\n💃${ settings.path } successfully updated\n\n` )
+		);
 	}
 }
diff --git a/includes/admin/js/perflab-plugin-management.js b/includes/admin/js/perflab-plugin-management.js
index 45200150e8..677d5584fb 100644
--- a/includes/admin/js/perflab-plugin-management.js
+++ b/includes/admin/js/perflab-plugin-management.js
@@ -9,15 +9,15 @@
 			typeof settings.data === 'string' &&
 			settings.data.includes( 'action=install-plugin' )
 		) {
-			var params = new URLSearchParams( settings.data );
-			var slug = params.get( 'slug' );
+			const params = new URLSearchParams( settings.data );
+			const slug = params.get( 'slug' );
 
 			// Check if 'slug' was found and output the value.
 			if ( ! slug ) {
 				return;
 			}
 
-			var target_element = $(
+			const target_element = $(
 				'.wpp-standalone-plugins a[data-slug="' + slug + '"]'
 			);
 			if ( ! target_element ) {
@@ -30,15 +30,15 @@
 			 * the core changes have taken place.
 			 */
 			setTimeout( function () {
-				var plugin_url = target_element.attr( 'href' );
+				const plugin_url = target_element.attr( 'href' );
 				if ( ! plugin_url ) {
 					return;
 				}
-				var nonce = target_element.attr(
+				const nonce = target_element.attr(
 					'data-plugin-activation-nonce'
 				);
-				var plugin_slug = target_element.attr( 'data-slug' );
-				var url = new URL( plugin_url );
+				const plugin_slug = target_element.attr( 'data-slug' );
+				const url = new URL( plugin_url );
 				url.searchParams.set( 'action', 'perflab_activate_plugin' );
 				url.searchParams.set( '_wpnonce', nonce );
 				url.searchParams.set( 'plugin', plugin_slug );
diff --git a/includes/admin/load.php b/includes/admin/load.php
index 3b89a6db8d..0684adea70 100644
--- a/includes/admin/load.php
+++ b/includes/admin/load.php
@@ -131,8 +131,8 @@ function perflab_render_pointer( $pointer_id = 'perflab-admin-pointer', $args =
 	<script id="<?php echo esc_attr( $pointer_id ); ?>" type="text/javascript">
 		jQuery( function() {
 			// Pointer Options.
-			var options = {
-				content: '<h3><?php echo esc_js( $args['heading'] ); ?></h3><p><?php echo wp_kses( $args['content'], $wp_kses_options ); ?></p>',
+			const options = {
+				content: <?php echo wp_json_encode( '<h3>' . esc_html( $args['heading'] ) . '</h3><p>' . wp_kses( $args['content'], $wp_kses_options ) . '</p>' ); ?>,
 				position: {
 					edge:  'left',
 					align: 'right',
@@ -143,7 +143,7 @@ function perflab_render_pointer( $pointer_id = 'perflab-admin-pointer', $args =
 					jQuery.post(
 						window.ajaxurl,
 						{
-							pointer: '<?php echo esc_js( $pointer_id ); ?>',
+							pointer: <?php echo wp_json_encode( $pointer_id ); ?>,
 							action:  'dismiss-wp-pointer',
 							_wpnonce: <?php echo wp_json_encode( wp_create_nonce( 'dismiss_pointer' ) ); ?>,
 						}
@@ -305,17 +305,13 @@ function perflab_deactivate_plugin() {
 	}
 
 	// Deactivate the plugin in question and return to prior screen.
-	$do_plugin_deactivation = deactivate_plugins( $plugin );
-	$referer                = wp_get_referer();
-	if ( ! is_wp_error( $do_plugin_deactivation ) ) {
-		$referer = add_query_arg(
-			array(
-				'deactivate' => true,
-			),
-			$referer
-		);
-	}
-
+	deactivate_plugins( $plugin );
+	$referer = add_query_arg(
+		array(
+			'deactivate' => true,
+		),
+		wp_get_referer()
+	);
 	if ( wp_safe_redirect( $referer ) ) {
 		exit;
 	}
diff --git a/load.php b/load.php
index e3bf77eabd..172492b5b6 100644
--- a/load.php
+++ b/load.php
@@ -177,7 +177,7 @@ function perflab_maybe_set_object_cache_dropin() {
 		 * Previous versions of the Performance Lab plugin were renaming the
 		 * original object-cache.php file and then loading both. However, due
 		 * to other plugins eagerly checking file headers, this caused too many
-		 * problems across sites so it was decided to remove this layer.
+		 * problems across sites, so it was decided to remove this layer.
 		 * Only placing the drop-in file if no other one exists yet is the
 		 * safest solution.
 		 */
@@ -249,7 +249,7 @@ function perflab_maybe_remove_object_cache_dropin() {
 		 * override the Performance Lab file. This is only relevant for
 		 * backward-compatibility with previous Performance Lab versions
 		 * which were backing up the file and then loading both.
-		 * Otherwise just delete the Performance Lab file.
+		 * Otherwise, just delete the Performance Lab file.
 		 */
 		if ( $wp_filesystem->exists( $dropin_backup_path ) ) {
 			$wp_filesystem->move( $dropin_backup_path, $dropin_path, true );
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
index b1caff17b0..02b0de739d 100644
--- a/phpstan.neon.dist
+++ b/phpstan.neon.dist
@@ -10,3 +10,5 @@ parameters:
 		- uninstall.php
 	scanDirectories:
 		- vendor/wp-phpunit/wp-phpunit/
+	dynamicConstantNames:
+		- PERFLAB_OBJECT_CACHE_DROPIN_VERSION