blazor-docs/knowledge-base/common-upgrade-breaks-css-theme-styles.md

title	description	type	page_title	slug	position	tags	ticketid	res_type
Version Update Breaks UI Component Styling	How to resolve broken CSSS theme styles after version upgrade of Telerik UI for Blazor	troubleshooting	Version Update Breaks UI Component Styling	common-kb-upgrade-breaks-css-theme-styles		css, styling, upgrade	1541420, 1564763, 1575968, 1578100	kb

Environment

Product

UI for Blazor

Description

The UI components do not render and look properly after version update.

How to resolve UI (styling) issues after NuGet package version upgrade? Where do I get the new theme CSS stylesheet?

Steps to Reproduce

Upgrade the Telerik UI for Blazor version (NuGet package). The component styling breaks. If the previous version is restored, the styling is OK.

Possible Cause

The application is using an outdated CSS theme or swatch.

Solution

To resolve the problem, follow the [recommended UI for Blazor upgrade procedure]({%slug upgrade-tutorial%}):

• If using the [Telerik CDN]({%slug common-features-cdn%}) - update the [stylesheet file URL]({%slug themes-overview%}#using-a-theme) to the correct version.
• If using a local CSS file in wwwroot - replace the stylesheet with a compatible one. If the application is using a [custom theme, then recreate it]({%slug themes-customize%}#import-custom-theme).
• If using static assets from the NuGet package - clear the browser cache and [add a cache buster for the Telerik CSS and JavaScript files]({%slug common-kb-browser-cache-buster%}).

A version update might break custom application CSS styles that are outside the Telerik theme. In this case, then check if the component HTML rendering or CSS classes have changed, and adjust the custom CSS code.

See Also

• [Telerik UI for Blazor version upgrade steps]({%slug upgrade-tutorial%})
• [Troubleshooting JavaScript errors after version upgrade]({%slug common-kb-cannot-read-properties-of-null-reading-addeventlistener%})