Solr Upgrade Notes

This section provides changes to Solr in recent releases that you should be aware of before upgrading. These notes highlight the important changes that may impact the largest number of implementations. It is not a comprehensive list of all changes to Solr in any release.

When planning your Solr upgrade, consider the customizations to your system and review the CHANGES.txt file found in your Solr package. That file includes all the changes and updates that may affect your existing implementation.

Detailed steps for upgrading a Solr cluster are in the section Upgrading a Solr Cluster.

How to use the Major Changes pages

The Major Changes pages are grouped in two ways:

  • For Solr versions 9.y+: The Major Changes in Solr x (e.g. Major Changes in Solr 9) pages include all changes included in any x.y release. Therefore Major Changes in Solr 9 includes all changes in any Solr 9.x release.

  • For Solr versions 6.y-8.y: The Major Changes in Solr x (e.g. Major Changes in Solr 8) pages include all changes from Solr (x-1).0 to Solr x.0. Therefore Major Changes in Solr 8 includes all changes from Solr 7.0 to Solr 8.0, starting with Solr 7.1.

In these pages, the first section describes planning for an upgrade to that major version from the previous major version, including system requirements, rolling upgrade concerns and re-indexing recommendations. All other sections are version-specific and include relevant changes in each minor version.

It is imperative to carefully review each section for the versions preceding and including the version you are upgrading to. (i.e. If you are upgrading from Solr 8.9 to 9.2, you will need to read the upgrade notes for 8.10, 8.11, 9.0, 9.1 and 9.2)

Upgrading to 9.x from 8.x Releases

The upgrade from 8.x to Solr 9.x introduces several major changes that you should be aware of before upgrading. These changes are described in the Major Changes in Solr 9 page. It’s strongly recommended that you thoroughly review that page before starting your upgrade.

If you run in SolrCloud mode and use SolrJ’s CloudSolrClient, you must first upgrade SolrJ to a version 8.10 or higher before upgrading the cluster to 9.0.
Rolling upgrades from Solr 8 to Solr 9 require first upgrading the cluster to version 8.7 or newer.

Upgrading from Pre-8.x Versions

Users upgrading from versions prior to 8.x are strongly encouraged to consult CHANGES.txt for the details of all changes since the version they are upgrading from.

The upgrade from 7.x to 8.0 introduced several major changes that you should be aware of before upgrading. Please do a thorough review of the section Major Changes in Solr 8 before starting your upgrade.

A summary of the significant changes between Solr 6.x and Solr 7.0 is in the section Major Changes in Solr 7.