If you’re running IntelliJ IDEA 15 Ultimate, you can sometimes see a confusing message in the Updates dialog, saying that you can evaluate the new version for 30 days, or buy a license key or upgrade online–regardless to the active state of your subscription.
We apologize for this, and promise to fix it in the minor update that we’ll be releasing within several days. Meanwhile, simply ignore this message. Thanks for your patience!
The JetBrains Team

I was quite surprised to see this and wrote an email to sales support to clarify that; this blog post serves as an answer, thanks!
Btw in the meantime, you can simply install Idea 16.1 from scratch, import settings from previous version, and all will work, it will correctly take your license with the correct expiry and fallback version.
Came here to see if I’m the only one with this problem (as I haven’t seen it in the comments of the release blog post a few days ago) – thanks!
I am installing intellIJ idea 16.0. I want to suppress update auto check..so I include update.xml file into MSI package..after adding tha I didn’t get the installation complete dialog which contains settings backup from previous version.anyone tell me the idea