The MacBook Air is one of the most thinnest notebook when it was introduced to public by the late Steve Jobs in 2008. Its performance was good although it does not have a retina display. In those days, a lightweight and cheaper laptop which is called a netbook, is trying to gain its momentum when people prefer to get tablet instead of PC or laptop.
At that time, a 4GB memory and 128GB storage is enough. But in today’s usage, it does impact your productivity. Apple has made the SSD storage can be upgrade. But the memory was soldered onto the board and it is not possible to swap the memory units. You can get a board from another MacBook Air that already comes with 8GB of RAM but the unit is expensive.
But REWA Technology had show a method to upgrade the MacBook Air memory. But it does require a lot of steps to complete the process.
Taking out the board itself is a risky process. All ribbons and wires connected to the board need to be safely taken out before the memory units need to be heated with the heat gun. Then, you need to unsolder all memory pins before replacing it with a new RAM.
It is possible to upgrade your 4GB MacBook Air to 8GB of RAM memory but it does require skills to do it since the board is really sensitive to heat.