Welcome betty577, If I understand your question, you are attempting to grasp what is meant by a 'previous generation' Kindle Fire. Most likely a comment on a 'previous generation' is referencing a 2nd gen device, previous years 2012 sell off as opposed to the currently available 3rd gen 2013 release. Although this may be a bit techie, it does list the individual devices by generation.
https://developer.amazon.com/public/solutions/devices/kindle-fire/specifications/01-device-and-feature-specifications I purchased a KF HD7 2nd gen back in Nov 2013 when the 3rd gen devices hit the shelves for the 2013 holiday season. Quite pleased with the device so far, the Dolby (tm) sound is awesome and the video quite acceptable. The camera is quite handy, although a rear facing one would be a nice addition.Battery life for reading without WiFi connected is about eight hours, three-five hours while surfing the web. Note that the newer 3rd gen KF HD doesn't have a front facing camera. Check this out for pictures and overview:
http://en.wikipedia.org/wiki/Amazon_Kindle KF 1st gen Fire OS 1 on September 28, 2011 KF HD 2nd gen announced on September 6, 2012 KF HDX 3rd gen announced on September 25, 2013 Should you be purchasing online, Make sure you match the device type with the specs to avoid disappointment. Screen size 7" vs 8.9" HD vs HDX 8Gig vs 16Gig and opt camera on older HD7 Is the charger included? Mine only had a PC USB charging cable - takes 12 hours to charge. $15 micro-USB quick charger available at Target The one in the ad mentioned in the previous post appears to be a 3rd gen without the camera. [Fast 1.5GHz dual-core processor] Hope that answers your concerns. Robin