Which PHP 5.X version should be considered as Required

I have such question to supporters of older versions ..
Why you will need CI 4 to build applications for PHP 5.3 or PHP 5.4 Servers...
You can use easier CI 3 and thats it all..

I don't need to build applications for 5.3 or 5.4 servers now, but I may not be so lucky at my next job.

CI 2 will be unsupported in 6 months, how long will CI 3 be supported after CI 4 is released? Why would you support the use of an EOL framework when you are so opposed to supporting the use of a version of PHP which has reached EOL (5.3) or even one which is still supported (5.4), but which may reach EOL by the end of the development period for CI 4?

What features in 5.5 or 5.6 are going to make CI 4 so much better than it would be if it targets 5.4?

This is what I don't understand with people that want the framework to target 5.6 or PHP 7. Just because the framework supports PHP 5.4 doesn't mean you have to use it yourself.

Answer: Just because the current way is to Wait .. CI 3 doesn't is based on PHP 5.2 which is out of date.
CI 4 can get next year or even after it..
At this time many other frameworks and developers will already be focused on PHP7 and we will still keeping the old 5.4 as our Base line.. 
I know that you can run newer PHP version with CI 2/3 but the point is all developers to move ahead not just to be stucked at 1 place so long.

Even linux distributions at the moment are using PHP 5.4/5.5 as stable versions.. in 1 year I suppose that the stable will be 5.5/5.6..

As one kids song... "Let it go, let it go.."

P.S> By the way CodeIgniter lost a lot of good developers (who started using mostly laravel) , just because it was too out of date in development process.
Focusing old PHP versions which are security holes... We have to think for the future not for now or for the past..

I don't think that CI future is supporting BAD practises as using old php versions in development or at productions and etc..

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