Incompatible WP 5 Notice

wp5_incompatible_notice

/*======================================
  WARNING FOR UPDATES PAGE
========================================*/
	
function wp5_incompatible_notice() {
	
	$screen = get_current_screen();
	
	// Make sure we're in the correct page
	if ( 'update-core' === $screen->id ) {
		
		echo '<div class="error notice">
			      <p>This site is incompatible with <strong>WordPress 5</strong>. <strong>DO NOT UPDATE!</strong></p>
			 </div>';
		
		echo '
			<script>
			    jQuery(document).ready( function($) {
					$("#upgrade").prop("disabled", true);
					$("#upgrade").removeClass("button-primary").addClass("button-disabled");
				})
			</script>
		';
	} elseif ( 'dashboard' === $screen->id ) {
		echo '<div class="error notice">
			      <p>This site is incompatible with <strong>WordPress 5</strong>. <strong>DO NOT UPDATE!</strong></p>
			 </div>';
	}
	  
}

// Check if the culprit plugin is active
if ( in_array( 'multiple-content-blocks/multiple-content-blocks.php', apply_filters( 'active_plugins', get_option( 'active_plugins' ) ) ) ) { 
	
	add_action( 'admin_notices', 'wp5_incompatible_notice' );

}