Re: Unable to upgrade Lucene 6.x index using IndexUpgrader

Anticipating your next question “why can’t you use an index created 2 or more versions ago”, these two quotes were helpful for me to get my head around it. It’s _always_ been the case that going from X to X+2 has been unsupported, it’s just that the failures wouldn’t necessarily be obvious. Luce

Re: Unable to upgrade Lucene 6.x index using IndexUpgrader

Same as I answered in SOLR-13487: Note that you'll probably need to re-index from scratch due to changes in 8.0, see https://builds.apache.org/view/L/view/Lucene/job/Solr-reference-guide-8.0/javadoc/indexupgrader-tool.html