Good minimum PHP (and MySQL) version to develop for?

dotnotwhat

What are people's views on defining a minimm PHP version required for their apps?

I want my current app to run on the majority of web servers out there with no changes required by the end-user. Up to now I have managed to avoid (or workaround) anything that requires PHP > 4.1 and possibly 4.0.1 but am wondering if I would actually be excluding a lot of users if I started capatilising on features only present in PHP 4.3 upwards for example.

The same goes for MySQL, I currently make sure everything works in 3.23.23 but there are features of more up to date versions of MySQL I'd like to commonly use where possible.

planetsim

Ok firstly this should probably be in the General Forum. Getting to the point.

Usually you can tell by the big guys for example vBulletin and PHPBB are all dropping support for < 4.3 I think well at least vBulletin has done so PHPBB is on the way with v2. A few other big apps are doing so, osCommerce I think is on the way however I dont really follow it much. I do know though that a lot of this is happening to be ready for PHP 5 support.

Depending on the SQL Queries your running if they are relatively simple you could probably keep support for 3.23.x, however in things Ive run although I state that 3.23 should work I dont actually test for it (which is a bad thing), however 4.0.x is starting to get on quiet a few servers now Ive realised.

dotnotwhat

Thanks planetsim.

That's very useful to know. I wil check out the requirements set by some other mainstream php apps and post the results here in case it is of interest to anyone else.

I really should have put this in the general forum so hopefully a mod could move it.

Drakla

So far the only problems I've come across when developing for old mysql installs is

a) No subqueries, obviously

b) No delete with ORDER BY and LIMIT - AHhHHHHh! It doesn't just bomb telling you the query is naff, it just goes ahead and deletes everything it feels like, cackling away to itself.

The was one more thing, but it was really obscure and I can't think of it. If I do a grep for swearing in comments I'll probably find it.

Ahh, UNION was the other, but you can just use CREATE TEMPORARY TABLE foo AS SELECT fields FROM wherever, then follow with an INSERT SELECT.

twoeyes

There is no minimum, it depends on what kind of application you are developing and how it would benifit from the added functions and/or features. There are also many work arounds for people with older PHP versions. For instance, if you're using file_get_contents() (not available in < 4.3) then just write a function:

if(!function_exists("file_get_contents")) {
function file_get_contents($file) {
// use something else to perform the same function
}
}

This type of workaround can be done with most new features, since not many new language constructs (at least not any that added new functionality) were added in PHP4's lifespan (normally those are reserved for major version changes ala php5).