Programming languages evolves with the need to the developers, but not all of them evolves at the same speed and sometimes some languages stays almost the same for decades. Is this a sign of stagnation? Is it possible to evolve a language without breaking retrocompatibility? This talk will cover how Python and Javascript approached the problem in a radically different way, with their pro and cons and with the consequences on the community. The main points of this talk are the comparation of the new features in both languages and strategies used to port or run the code on different versions.