I've updated the string library to support Stardog 7. In addition I've removed the array functions. They only worked on strings and have been superseded by the new ArrayLiteral support in Stardog 7. (thus the reason for all the ArrayLiteral questions). Functions taking or producing arrays have been updated to use the new ArrayLiterals.
This includes some additional split functions like splitByCharacterType and Join functions, join and joinWith that will concatenate an array of strings on a join token.
https://github.com/semantalytics-stardog/kibbles-string
I realize that the documentation is lacking but if someone asks I'll put some more effort into it. I was thinking of using the function ontology to do it and maybe even have the plugin itself generate it so it's self documenting that way you can do a sparql query for how to use it.