Loki is going to be the new version of elementary OS and it is going to be based on Ubuntu 16.04 LTS. This version of Ubuntu will be released next month and hopefully elementary OS 0.4 Loki will follow it shortly. There is no testing ISO available for Loki right now but according to WOGUE Google+ page the elementary team is going to release one soon.
Alex Diavatis – the author of WOGUE Google+ page – has demoed the new elementary OS running on top of Ubuntu 16.04 beta. It’s not using the default theme but it still looks awesome and the animations are really eye catching.