I'm a little new to Apache Solr and I'm trying to upgrade a Solr 1 store to Solr 6. The creators posted a quick upgrade guide, but since they initially started out using Lucene, I'm wondering if I need to perform some kind of upgrade with Lucene as I upgrade my Solr indices. I came across the Apache Solr Index Upgrader tool, but I'm not sure if I should use it. The program I have uses a SQL database for referencing and I'm trying to minimize any potential corruption in the process. Could someone better explain the interaction between Solr and Lucene and whether it would be possible to use the Index Upgrader tool to upgrade Solr stores with third-party programs/providers?
https://lucene.apache.org/solr/guide/6_6/indexupgrader-tool.html
