File: //proc/self/cwd/wp-content/plugins/wp-whatsapp/includes/Fallback.php
<?php
defined( 'ABSPATH' ) || exit;
add_action(
	'admin_notices',
	function () {
		if ( current_user_can( 'activate_plugins' ) ) {
			?>
<div class="notice notice-error is-dismissible">
	<p>
		<strong><?php esc_html_e( 'It looks like you have another WhatsApp version installed, please delete it before activating this new version. All of the settings and data are still preserved.', 'wp-whatsapp' ); ?>
			<a
				href="https://ninjateam.gitbook.io/whatsapp-for-wordpress/getting-started/how-to-update"><?php esc_html_e( 'Read more details.', 'wp-whatsapp' ); ?></a>
		</strong>
	</p>
</div>
			<?php
			// phpcs:ignore WordPress.Security.NonceVerification.Recommended
			if ( isset( $_GET['activate'] ) ) {
				unset( $_GET['activate'] );
			}
		}
	}
);