The distributions have been updated to include Ubuntu Zesty 17.04. Ubuntu Zesty is a non-Long Term Support release so we recommend only customers who are OK with a full distribution upgrade every 9 months to use this version of Ubuntu. The release notes are here. Other distributions were updated to more recent packages so that full system updates do not take as long.
The next release will be for Debian Stretch, slated to drop in June 2017.