Blazor — End of Support for Bootstrap v4 (v26.1)
As previously announced, DevExpress Blazor deprecated support for Bootstrap v4 in our v25.1 release cycle. With v26.1, we expect to complete our transition away from Bootstrap v4 by removing support as follows:
- The
DevExpress.Blazor.Themespackage will no longer include Bootstrap v4-based stylesheets for classic themes (Blazing Berry, Blazing Dark, Office White, Purple). - All remaining theme dependencies on Bootstrap v4 or default CSS will end.
This post explains why this change was made, how it impacts existing apps, and what actions you may need to take before upgrading.
Bootstrap v4: End-of-Life Status
Bootstrap v4 was a reliable and widely used CSS framework for many years. It reached its end of life (EOL) in 2023 and is no longer maintained or updated.
Continuing to leverage a non-supported framework increases maintenance costs and introduces potential long-term risks for apps that rely on the framework. To align with modern development practices and ensure a stable platform for future releases, DevExpress Blazor will end Bootstrap v4 support once we officially ship v26.1.
Bootstrap v5 Support
In our v25.1 release cycle, we formally deprecated Bootstrap v4 support and marked the BootstrapVersion global option as obsolete (see the following breaking change notice for additional information in this regard: GlobalOption.BootstrapVersion is now obsolete).
This announcement gave customers time to transition away from Bootstrap v4 and address styling requirements ahead of full removal.
Impact on Existing Apps
You should review your project if any of the following applies to your DevExpress-powered Blazor app:
- You explicitly set Bootstrap version to
v4. - You did not specify Bootstrap version prior to v25.1.
- You applied a DevExpress classic theme (Blazing Berry, Blazing Dark, Purple, or Office White) using a Bootstrap v4-based stylesheet:
<link href=@AppendVersion("_content/DevExpress.Blazor.Themes/blazing-berry.bs4.min.css") rel="stylesheet" /> - Your custom styles relied on Bootstrap v4 classes.
Steps to Take Before You Upgrade to v26.1
Before upgrading to v26.1, you must:
- Remove any usage of
BootstrapVersion=v4. - Migrate custom styles from Bootstrap v4 to Bootstrap v5 where necessary.
- Replace Bootstrap v4-based theme stylesheets with supported alternatives. Please review the following help topic for additional information: DevExpress Blazor Themes.
Once you upgrade to v26.1, thoroughly test layouts and component appearance.
Your Feedback Matters
If you have questions about this change or need personal assistance, feel free to contact us via the DevExpress Support Center.
