# Core Engine Release 4.21

October 2024

We upgraded! What's new? Learn more about new features, technical changes and solved bugs in 4App Core Engine.

Note on upgrading: If you skip a version when upgrading, check all release and patch notes in between for important information. They apply cumulative.
Note on individualization: If your 4ALLPORTAL is highly customized or if you installed individual apps, please contact your implementation partner before upgrading. We recommend checking your custom contents, especially layouts and object renderers, carefully after an upgrade.

# Technical Changes & Admin Instructions

# Improved Error Handling

The backend now returns the new ErrorResponse which we implemented with Core Engine version 4.16. This results in more differentiated error messages and improved logging.
In addition, errors on OpenApi method calls will be returned with the new ErrorResponse, rather than just a redirect to a 404 page.
Further information: Open API ErrorResponse

# Solved Bugs

Fix indicating the selected startup module in a user's personal settings only on mouse-over. The selected module is now always indicated.

← Core Engine Release 4.20 Core Engine Release 4.22 →