No. The Series 10 finalé "World Enough and Time"/"The Doctor Falls" revealed that the "Harold Saxon" incarnation of the Master survived his battle with Rassilon & crossed his own timeline to meet his future incarnation Missy (short for "Mistress"). The Missy incarnation stabbed him in the back (literally), causing him to regenerate into her. He then used his laser screwdriver to shoot her (also in the back), apparently killing her outright. However, as at least two of the Master's incarnations have shown (in "Doctor Who", the TV movie, & in "The End of Time"), even death can't be relied on to stop the Master permanently.