To upgrade from a previous version, see the following steps.
Configuration data are in the following files:
fess_basic_config.bulk and fess_user.bulk from Backup page (For more details, see Backup of Administration Guide)
system.properties in /etc/fess or app/WEB-INF/conf
fess_config.properties in /etc/fess or app/WEB-INF/conf
Stop Fess and then install RPM/DEB package. For the instruction, see Installation in Installation Guide.
To upgrade to Elasticsearch 8, remove old indices and then upgrade Elasticsearch package. For Elasticsearch plugins, if you upgrade Elasticsearch, re-install all Elasticsearch plugins for the correct Elasticsearch version.
Check and merge settings in fess_config.properties, and then start Fess.
Upload fess_basic_config.bulk and fess_user.bulk on Backup page to restore data.
To create new search indices, start Default Crawler job on Scheduler page.