See https://github.com/glpi-project/glpi/pull/5968 (this is still a WIP, and there is no planned date).

Will be part of 9.5.0

work started: https://github.com/glpi-project/glpi/pull/6088

Impacts/dependencies feature started and will be shipped in 9.5: https://github.com/glpi-project/glpi/pull/5954

Feature will be shipped for 9.5

Work in progress : 

https://github.com/glpi-project/glpi/pull/5892

work for impacts/dependencies graphs is in progress: see https://github.com/glpi-project/glpi/pull/5954

done in https://github.com/glpi-project/glpi/pull/6008