---
title: "Issues after upgrade | Customer's Canvas On-Premises"
canonical: "https://customerscanvas.com/docs/on-premises/design-editor/iframe-api/troubleshooting/upgrade-issues/"
---

# Issues after upgrade

> When you upgrade the Design Editor to version 4.0, the preloader does not appear in the Design Editor.

:::important
To ensure a smooth transition to a new version of the Design Editor, follow [our step-by-step instructions](https://customerscanvas.com/docs/on-premises/design-editor/it-ops/install/update.md).
:::

## Missing Preloader

### Solution

Design Editor 4.0 introduces breaking changes in the preloader feature. Now, you set up this feature through the `preloader` object in [IConfiguration](https://customerscanvas.com/docs/on-premises/design-editor/iframe-api/customization/preloader.md), which enables the preloader by default. So, if you already customized the preloader and want to keep your implementation, please set the `preloader.enabled` property to `false` when migrating from any 3.x.x release to 4.x.