The following notes describe changes to Solr in recent releases that you should be aware of before upgrading.
These notes are meant to highlight the biggest 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 you have made to your system and review the
CHANGES.txt file found in your Solr package. That file includes all of the changes and updates that may effect your existing implementation.
Detailed steps for upgrading a Solr cluster can be found in the section Upgrading a Solr Cluster.
Upgrading from Any 6.x Release
The upgrade from Solr 6.x to Solr 7 introduces several major changes that you should be aware of before upgrading. Please do a thorough review of the section Major Changes in Solr 7 before starting your upgrade.