PKI supports both Tomcat 7 and 8, but it's not possible to create a single Eclipse project that supports both versions at the same time since some of the source codes and dependencies are different. Also, Eclipse does not support creating multiple projects in the same repository since the project files will conflict (https://bugs.eclipse.org/bugs/show_bug.cgi?id=78438). So right now there is only one PKI Eclipse project and it only works on Fedora 22 which uses Tomcat 7.

Since Fedora 23 or newer uses Tomcat 8, eventually the project needs to be updated to use Tomcat 8 in master branch, but that means it will no longer be possible to use Fedora 22 for new development. For older branches the Eclipse project will continue to work on Fedora 22 using Tomcat 7.

Another option is to create project files in separate folders (e.g. pki/tomcat7 and pki/tomcat8), then anybody who wants to use Eclipse will need to copy the appropriate project files manually to the project's root directory.