Struts devs have updated the 4.0.x struts2-bootstrap-plugin to work on
the latest version of struts
dependency>
<groupId>com.jgeppert.struts2.bootstrap</groupId>
<artifactId>struts2-bootstrap-plugin</artifactId>
<version>4.0.2-SNAPSHOT</version>
</dependency>
It will be maintained also going forward (hopefully).
Here is an upgraded version that I have done, only a few changes are needed.
https://github.com/gregh3269/roller/tree/Upgrade_to_Struts-6.3.0.1
I have tested it and looks the same. Can you have a look? Need to get
off the 2.5.x branch.
Cheers Greg