Just look in the root folder of the laravel installation. If you can find a vendor folder, it's Laravel 4 or 5, if not it is Laravel 3.

An upgrade would be pointless, because the whole structure of laravel has changed from 3 to 4.

Laravel 4 is completly different from Laravel 3, because l3 had bundles, a different folder structure and no support for composer and there is also no support for laravel 3 anymore.

If it's a small project, I would suggest you to switch to laravel 4 and start from beginning, in any other case continue use of laravel 3.

Ok, thanks. So i have lavarel 3. No support, kind of means security holes will not be fixed. Right?

Also, i found that lavarel 3 breaks on php5.5 because of a yield() function that in 5.5 is a reserved word. This won't be fixed either?

When did support for L3 stop?

There is no official "stopping" of support, it's likely that if a major security flaw was found, it would be fixed by somebody (open source). General bug fixes (such as updating PHP support) are unlikely to happen officially.

However, L3 is getting quite old now and I don't know how many devs would be keeping an active eye on it and any fixes it may need, L4 was released in 2013 and L5 is due later this month.