You should be able to go straight to 5.3.1 Solr/Lucene tries to guarantee that the indexes are readable one major version back, i.e. 5.x Solr/Lucene code should be able to read any 4.x index. New segments are written in the most modern format, so over time all the 4x remnants should disappear.
You can also use the IndexUpgrader tool to make upgrade the index, see: https://lucene.apache.org/core/5_3_1/core/org/apache/lucene/index/IndexUpgrader.html take a backup first of course ;) You can also optimize after upgrading to 5.3.1 which will rewrite all the segments too, but personally I'd run the IndexUpgrade by preference unless it's an index that doesn't change very often if at all. All that said, you should simply be able to install 5.3.1 and start running, running the IndexUpgrade tool or optimizing isn't actually necessary. Best, Erick On Thu, Nov 5, 2015 at 1:28 AM, Julien David <j.da...@decalog.net> wrote: > Seems I'ill need to upgrade to 5.3.1 > > It is possible to upgrade from 4.9 to 5.3 or do I need deploy all > intermediate versions? > > Thks > > > >> > > >
