Yes also the 530 can get windows 10.
At he moment the preview of windows 10 is available for only a few devices and one of them is the 630 which also has a 512 memory.
The 530 however can not yet participate in the preview.
So you have to wait till that is possible (if you wanted it)
And otherwise you have to wait till the official release wich still can be more than 6 month
That's probably possible but personal I do not think it's a good idea.
But if you do be aware of the risks and do not complain if it fails.
(Worst case is that you brick your phone for good and have to buy a new one)
Unofficial??? Ow you naughty.
Despite of all the warnings there are no reports of any phonebrick.
But keep in mind there is always a first.
Just do your homework and readings.
The problem i foresee are in the next following updates. As soon as the firmware is going to be pushed.
Therefore it's important that you also follow the final steps.