At Polarion, we've been doing agile development since 2005. Our approach, with 2-week sprints, helps us develop new features and improvements in short bursts, culminating with a Service Release every quarter - releases of a product we have used ourselves every day. Then, early each year we roll up all the new features and improvements from the Service Releases, add a few more, and release a new major version.
For our customers, this incremental approach, with predictable, reliable, backward compatible updates means that any issues with the software are resolved much faster and they receive access to road-mapped new features sooner. And, very importantly, it reduces the risk and eliminates the complexity of updating to a new major version. So while we call Polarion 2016 our latest major version, it's no more complex or risky than the updates you've been installing for the past year.
To see what we've delivered since the Polarion 2015 release, check out these blog posts:
What's New and Noteworthy in Polarion 2015 SR1
What's New and Noteworthy in Polarion 2015 SR2
What's New and Noteworthy in Polarion 2015 SR3