Improved user interface and new design for the recent/popular homepage and admin console
Map viewer improvements (eg. projection switcher, better WFS2 support, TMS support, HTTPs redirect support, WPS support, external lviewer support, legend panel)
Thesaurus / Better Registry support and GEMET update to version 4.1.2
Harvesting / WFS features improvements (eg. asynch indexing for better performances, precision model configuration, CDATA support, Elasticsearch 6.4.x support)
Performance improvements on indexing and JS & LESS compilation
Better HTTPs support
Security fixes and library updates
and more … see 3.6.0 issues and pull requests for full details.