I am using Solr 5.3.1 and wish to upgrade this to 6.5
To upgrade this i tried using CheckIndex and IndexUpgrader tool.
Initially i started with lucene-core-6.5.0 and lucene-backward-codec-6.5.0 as mentioned in their official docs. This is throwing org.apache.lucene.index.IndexFormatTooOldException. Then i tried using jars with version 5,4,3,2. when using lucene-core-2.9.4 it is throwing org.apache.lucene.index.CorruptIndexException: Unknown format version: -48132013 How is it possible to have an index with negative lucene version when i am using solr release version 5.3.1