How long till the iPhone 4 isn't supported?

I'm thinking of getting an iPhone 4 in the summer, however, how long until it isn't supported by apple - so you can't get apps and new iOS updates?

Since I know the iPhone 3GS is soon or perhaps even has been unsupported, surely meaning the iPhone 4 hasn't got years to go?

Thank you in advance.

Added (1). Also, has the iPhone 4S got a lot longer in comparison, or would it not be a big difference?

The IP4 is months away from being discontinued on release of the IP5S.

Apple only support LAST 3 iPhones, discontinued means no longer sold by Apple, any future upgrades are for supported phones some new apps just WON'T WORK

On 12/09/2012 IP5 announced IP 3GS DROPPED, like the year before IP4S IN, IP3G OUT. No maths IP5S IN…

It may be the cheapest when compared to other iPhones but to invest any money in an OVERPRICED device is a waste as in 2 years you will be using a 5 year old device that came out in 2010. Many many have already upgraded from the IP4 in 2012
http://www.itproportal.com/2012/09/06/8gb-iphone-4s-version-be-introduced-iphone-5-launch/
http://www.gsmarena.com/...ew-490.php

There are newer phones better phones and they cost a lot less, giving you more than the restrictive 8Gb on the IP4, You should look at eg Sam Gal ACE II or the Lumia 620 for phone with a secondary camera microSD expansion Wi-Fi, GPS, DUAL CORE… AND/ &/ PLUS/ + BLUETOOTH MEDIA TRANSFER (Sharing) which no iPhone even the IP5 has.
Here are the specs only if these phones are Gold Plated will it come in above the IP4
http://www.gsmarena.com/...hone2=5147