Yes it does. But there are currently no DCS 6.0 agents for Linux, only windows. If you have just linux endpoints, I would either not bother with the upgrade until 6.0 agents are available, or upgrade to 5.2.9.
Either way, the upgrade of the manager is very straight forward, just the standard things, backup database before doing it etc. But you may see some strange behaviour if you have a 5.2.8 agent on the 6.0.0 manager.
I suggest upgrading to 5.2.9, upgrade the agents to 5.2.9 and the policies to 5.2.9. Then when 6.0.0 agents are available for linux you can upgrade then.