LED Christmas Tree Lights

I bought a white – lighted Christmas tree that has 500 mini clear lights on it. My favorite color is blue, and I plan on replacing the clear lights with blue light bulbs that I will get from a few strands of blue Christmas lights.
All of the lights on my Christmas tree are regular mini lights. I can get regular mini blue  lights, but I have also seen M5 LED  lights that look like they may fit in the same socket as the mini lights.
I have to order all of my lights over the internet, so I can’t see if the mini lights and the M5 LED lights are the same size or not. I was wondering if the M5 LED lights are the same size as the regular mini lights, and if they are, can you plug M5 LED lights into a cord meant for mini light with out burning up the cord or damaging the LED bulbs?
The reason I am ordering the lights over the internet is because I am military – stationed over seas. Going to a local business is unfortunately not an option that I have…. although,  given the chance I would love to give my business to a business back home.