4.2 has far more artifacts in lightweight mode versus 4.1 on Linux.
4.1 player & 4.1 server = very few artifacts
4.1 player & 4.2 server = very high level of artifacts and missing icons and sections of the screen
4.2 player & 4.2 server = slightly better level of artifacts, but still many areas not correctly rendered. You have to hover your mouse over these areas to force it to display.