macbook - Can I upgrade RAM on late 2013 retina Mac Book Pro? - Ask Different
Per the teardown performed by iFixit, the RAM in Retina Displays is soldered to the logic board. It may be possible to undo the soldering and upgrade it, but the hassle is almost surely not worth it. https://www.ifixit.com/Teardown/MacBook+Pro+13-Inch+Ret...