PHP is what is it about these versions?

So if you if you pick up a book to learn PHP ah, you'll notice though they made the book may talk about what version of PHP that the book covers.

Or if you, if you download an open source Web application, you may see that that Web application requires a certain version of PHP.

And you may wonder why that ISS The thing that you have to understand about PHP as an interpreted language is that the interpreter has versions just like other programs or applications have versions, right?

Outlook or exchange or excel.

Any any application that you use has versions, and different versions have different features and functionality.

Programming languages are the same, so Version one has a certain feature set version to a certain feature.

Set version 4567 They all have their own feature sets, and so it's important, understand, when you code in PHP, the functions that you're going to be using will be based off of the P H P version that you're using.

So what happens is a lot of times and if you look at a function so the male function or print functions are different, different functions in a programming language think about those.

Is those air kind of like features in an application?

So when you go to G male female has certain features we go to snap or you go to Facebook.

There certain features well with programming languages.

What happens is that certain versions of the programming language they'll test out new features.

They'll they'll say, Well, this is how we've been doing email up till now this is the email function upto.

Now let's let's see if we can do mail in a different way.

Let's let's see if we can create a better function that's able to do what we've been doing before on Lee in a better way now.

Sometimes that works.

And so in future versions, the new function will replace the old function when sometimes it doesn't work.

There's a lot of functions that are created.

People think it's gonna be the greatest function.

The world this is this is People are gonna use the hell out of this function and the nobody uses it.

So the function sticks around for a couple of versions, and then it gets a drop, had a certain point.

So it's important to understand when you're coding and PHP and you're using functions that, depending on what version of PHP you're using, those functions may exist or may not exist in that particular version.

And so when you create your PHP code, you need to realize what what version of PHP you created that code for.

And then going forward, you need to either modify the code as versions of PHP change going to the future, or he simply stipulate that this PHP code needs to be run on version seven or version five or version former version three.

And so this is what happens.

This is where you get into problems with PHP again.

A lot of times with PHP, PHP gets written.

People don't think it's going to be that significant again.

Somebody creates something like inventory control system.

They figure.

They figure it'll be trashed within a year There.

They're just doing something for some little side project makes him a little side project easier, and then all of a sudden it's five years later, and the entire corporation is using that original code.

So one of the problems that that you have is when that code is written, it's It's using particular functions based off of the current version of PHP.

But then, as time goes by, new versions of PHP come out, new functions come out, but also functions are deprecating, functions are taken away.

And so one of things that you have to realize is if that you're going to continue using this code over the years, you either have to update the code as different versions come come online.

Or you just simply have to realize that this code can only be run on a server running PHP four, b two b three or PHP five so on and so forth.

So that's all we're talking about with PHP versions.

Now when you're doing simple code to be clear, when you're doing a relatively simple that's the stuff that will be talking about in this PHP track.

You should be fine more unless you should be fine.

It should issued work on whatever whatever PHP version that you're using, uh, where this really gets becomes.

More important is when you're doing Apple Web applications that have thousands of lines or tens of thousands of lines of code.

You're doing very, very special, very specific things.

Uh, that that's when things like PHP version can really come come out and really start to cause problems.

So this is important, Understand?

If you download and install a Web application and it's not functioning properly for some reason, ah, one of the reasons, maybe, is that you're using the wrong version of PHP for what that particular Web application was developed for.

So those were some of the things you should be thinking about with PHP versions, and that's why they matter.