Wether you are upgrading your board, changing out your battery or purchased the incorrect ESC, changing your ESCs voltage is an easy way to save yourself from a lengthy exchange process or some money you may have spent on a new ESC all together.
Your ESC should look a little like this when you start. All basic ESCs shipped by MBoards come with a protective paper layer.
Remove the paper layer. ***WARNING*** Take proper precautions when handling motherboards like this. Static shock can kill your ESC. To be safe do your best to ground yourself.
On the board, there is a grouping of 4 small squares labeled "6s" and "7s". If they aren't labeled refer to the reference photos to located them.
To change the ESCs voltage you simply have to connect the 2 squares that are labeled the desired voltage you are planning on using with a bit of solder. If the 4 squares are all disconnected the ESC is a 10s ESC, if the 6s squares are connected it's 6s, and if the 7s squares are connected then it's 7s. In the end, it should look like this:
And That's it! In this example we converted a Dual Hub Motor 10s ESC to a 6s ESC. Follow the same instructions for Dual Belt ESC as well. If you are converting the Single ESC then refer to the photo below if the squares aren't labeled on your ESC.