diff --git a/src/wp-admin/admin-header.php b/src/wp-admin/admin-header.php
index e1e9ba0f6562b..9de7b244b4cd5 100644
--- a/src/wp-admin/admin-header.php
+++ b/src/wp-admin/admin-header.php
@@ -191,8 +191,16 @@
 	$admin_body_class .= ' taxonomy-' . $current_screen->taxonomy;
 }
 
-$admin_body_class .= ' branch-' . str_replace( array( '.', ',' ), '-', (float) get_bloginfo( 'version' ) );
-$admin_body_class .= ' version-' . str_replace( '.', '-', preg_replace( '/^([.0-9]+).*/', '$1', get_bloginfo( 'version' ) ) );
+$version_without_tag     = strtok( get_bloginfo( 'version' ), '-' );
+$version_components      = explode( '.', $version_without_tag );
+$version_class           = 'version-' . implode( '-', $version_components );
+$admin_body_class       .= ' ' . $version_class;
+$branch_version_components = array_slice( $version_components, 0, 2 );
+if ( '0' === array_last( $branch_version_components ) ) {
+	array_pop( $branch_version_components );
+}
+$branch_class      = 'branch-' . implode( '-', $branch_version_components );
+$admin_body_class .= ' ' . $branch_class;
 $admin_body_class .= ' admin-color-' . sanitize_html_class( get_user_option( 'admin_color' ), 'modern' );
 $admin_body_class .= ' locale-' . sanitize_html_class( strtolower( str_replace( '_', '-', get_user_locale() ) ) );
 
diff --git a/src/wp-admin/customize.php b/src/wp-admin/customize.php
index 2065e55ffb3ce..5471a98c5b289 100644
--- a/src/wp-admin/customize.php
+++ b/src/wp-admin/customize.php
@@ -288,7 +288,7 @@
 							$class .= ' active';
 						}
 						?>
-						<button type="button" class="<?php echo esc_attr( $class ); ?>" aria-pressed="<?php echo esc_attr( $active ); ?>" data-device="<?php echo esc_attr( $device ); ?>">
+						<button type="button" class="<?php echo esc_attr( $class ); ?>" aria-pressed="<?php echo esc_attr( $active ? 'true' : 'false' ); ?>" data-device="<?php echo esc_attr( $device ); ?>">
 							<span class="screen-reader-text"><?php echo esc_html( $settings['label'] ); ?></span>
 						</button>
 					<?php endforeach; ?>