It depends what version of the licence you purchased B4A with.
It if was the Standard version you are entitled to 2 months free upgrades - I.e. if a new version comes out within two months of when you purchased B4A you are entitled to that new version.
If you purchased the Enterprise version it is the same except it is 2 years instead of 2 months that you get free upgrades.
Either way I expect that you would have received an email giving you the link to download the updated version. If you didn't get one I would think that you must have purchased the standard version, and it was more than two months before 2.7 was released.
The details for this are on the B4A web site - choose the Purchase link from the top:
http://www.b4x.com/android/purchase.html