The gang has moved up to monthly releases, so hot on the heels of the February updates are two new releases this week.
The latest stable release is OpenNMS 1.6.10. This release contains bug fixes and while not critical, all users of 1.6.x before 1.6.10 should consider upgrading.
The latest development release is OpenNMS 1.7.10. This has a rather large number of bug fixes and features, including the ability to use the remote monitors over HTTP, push collected data out over a TCP port, and the much talked about JasperReports integration.