Dropzone Commander is getting a new edition. Apparently it is supposed to drop at GenCon already. In the lead up TTCombat are publishing a series of articles on what changes with the new edition, dropping 2 - 3 a week.

They also already published the first article about the rules changes:
Army composition
Unit categories have been overhauled a bit. Now there are only the categories "Standard", "Vanguard", "Heavy", and "Support". Transports and commanders sit outside these categories. Vanguard, Heavy and Support each can't use more points than the Standard category in your army.

Also the battlegroups of the previous editions are gone and replaced with groups. Those are generally smaller and focused around squads and their transport rather than the multiple squads and their transports of the old battlegroup system. But TTCombat's Alex can explain it better than I can now. So go read the article if you are interested in more infos. ;P