Hello! Solr 4.2.1 is using Lucene 4.2.1. Basically Solr and Lucene are currently using the same numbers after their development was merged.
As far for Luke I think that the last version is using beta or alpha release of Lucene 4.0. I would try replacing Lucene jar's and see if it works although I didn't try it. -- Regards, Rafał Kuć Sematext :: http://sematext.com/ :: Solr - Lucene - Nutch - ElasticSearch > Hi, > Which lucene version is used with Solr 4.2.1? And is it possible to open it > by luke? If not by any other tool? Thanks > Thanks