Is it possible to use a Splunk 6 deployment server in a Splunk 5 environment? All of my forwarders/indexers/search-heads are splunk 5, but I'd like to try out the Deployment server functionality, if possible.
I beleive you should have no problem. Check this:
Compatibility between forwarders and indexers
I am using a Splunk 6 indexer/Deployment server and a Splunk 5/6 forwarders with no problem.