To ensure outdated versions are no longer posing a potential security risk, SAP removes SAPUI5 versions from the SAPUI5 CDN one year after their end of maintenance. In addition to this also patches of versions in maintenance which are older than one year will be removed. Details see SAP Note 3001696.

However at times if you are not following up with proper updating strategy you might run into issues such as below, and if this happens then you might observe Fiori applications have stopped functioning.

Security is a key concern for SAP, and as such, it makes significant investments across all product lines and adheres to all respective legal requirements. SAP is dedicated to identifying and resolving security risks that affect our cloud-based software and other products. Therefore it is always recommended to keep up with the latest patches on priority to protect your landscapes.

For SAP Business Technology Platform, recommendation is to always upgrade to the latest SAPUI5 version. It includes the latest capabilities, patches and security fixes.

Solution: Please refer to SAP Note 3001696

The note explains this topic in much more detail and also provides suggestions on what to do to solve this problem.

For security reasons you should upgrade regularly to newer patches and make sure, that for stability reasons you always refer to a specific SAPUI5 version instead of using the default version. Use the default version for testing purposes only. Reference Link

Do remember that when performing the update there might be other components that might be required to be included based on the package attributes since these packages are needed to ensure consistency. Should you have any issues or further clarifications on this then Of Course you could reach out to SAP for clarifications.

SAPUI5 Versions Maintenance Status: Link

Available SAPUI5 Versions on SAP Business Technology Platform: Link