I'm using the human GeCKO Library v2 from Feng Zhang Lab Plasmids (http://www.addgene.org/pooled-library/zhang-human-gecko-v2/) but the gene symbols are outdated (the library was published in 2015). To update them I tried to use this web tool http://www.genenames.org/tools/multi-symbol-checker/ but some gene symbols were not identified.
Is there a better way to update them?
I think you should contact the creators/authors. It's their tool and they're responsible for keeping it up to date. If it's not being maintained, maybe look for alternatives?
The problem is that the CRISPR experiment I'm analysing was already performed with this library... I'll try to contact the creators but I don't expect any answer.