The following table shows the compatibility of Gerrit Code Review with Elasticsearch.

Elasticsearch Version 2.14.x 2.15.x 2.16.x 3.x Notes
2.4.x 2.14.8 2.15.3   3.0.0 Support discontinued in 2.15.8, 2.16.1 and 3.0.0
5.6.x 2.14.8 2.15.3   3.0.0  
6.2.x 2.14.8 2.15.3   3.0.0  
6.3.x 2.14.10 2.15.3   3.0.0  
6.4.x 2.14.12 2.15.4 2.16 3.0.0  
6.5.x   2.15.8 2.16.1 3.0.0  
6.6.x   2.15.10 2.16.5 3.0.0  
6.7.x   2.15.13 2.16.8 3.0.0  
6.8.x   2.15.16 2.16.11 3.0.2  
7.0.x   2.15.13 2.16.8 3.0.0 See note below about upgrades
7.1.x   2.15.14 2.16.9 3.0.1  
7.2.x   2.15.15 2.16.10 3.0.2  
7.3.x   2.15.16 2.16.11 3.0.2  
7.4.x       3.0.3  

Indices created in Elasticsearch 5.x or earlier will need to be reindexed with Elasticsearch 6.x in order to be readable by Elasticsearch 7.x. See breaking changes in Elasticsearch 7.0 for details.