Yes that is last years model, the new models (for 2018) are releasing May 1st this year (so in like a week) and the media embargo for them lifts tomorrow so we'll get details of this years models and pricing.
A good thread to follow for this years tv:
http://www.avsforum.com/forum/166-l...ries-4k-hdr-roku-tvs-expected-may-1st-15.html
OLED is a type of tv.
In the current tv market the main types of tv's are LED and then OLED, each with their own advantages and disadvantages.
With LED tv's they are generally cheaper (because they are easier to make) and also the higher end LED tv's can get BRIGHT, like super-bright, which is good for showing off HDR and really makes it pop when it's being used.
However there are drawbacks to led tv's. The main drawback is what's known as "halo'ing," because of how led tv's work in a dark scene when you have a bright object on screen the tv has to send light to that specific area and this creates a "halo" of light around that object. However there are some ways to make this not as noticeable, such as FALD (Full array local dimming) which basically uses "zones" of leds turning on/off instead of the normal "edge lighting" (which sends light from the edge of the screen to that led). Most higher end led tv's use FALD and the more "zones" they have generally it means smaller halo's but they still aren't nearly as good as OLED's when it comes to true black colors and no halo'ing.
With OLED's they are able to turn on/off EACH led, that means that they are able to produce true blacks (because the led will be off, so no light). This means that night time scenes look simply amazing on an OLED tv generally and with HDR the contract between true black to highlights can look amazing.
The drawback to OLED's is burn in/image retention. Sort of like Plasma tv's if you watch a lot of static content (IE news stations or things with a static image on the screen) this can eventually "burn in" to the tv, however there are ways to combat this with many oled's having a built in cleaner and such to help stop this, and if you constantly vary what you watch and don't watch the same static thing for like hours and hours a day for weeks at a time you should be fine and not have an issue with it.
So basically to sum it up, led tv's - Great if you want a cheaper and "bright" tv and don't mind "halo'ing" when it comes to night scenes in movies/tv, oled tv's - overall the best picture quality but risk of burn in if you watch a lot of static content without changing it up.