So read in https://getsol.us/2020/02/13/we-love-package-updates-the-roundup-15/ that the NVIDIA 340.xx Driver has been depreciated. This does not affect either my System76 Thelio or Dell Optiplex 755 as they run AMD graphics. However, what used to be my main laptop and now a testing machine, an Alienware M15x - of which I have 2, has a NVIDIA GT216M [GeForce GT 240M), which uses the 340.107 driver. Oh well, when testing these days on these machines I usually just use the Nouveau driver anyway. Hard to believe these excellent laptops are now over 10 years old!!
I have a GT430 PCIe card in my 10 year old Dell Inspiron 580 running Mint 19.3. I switched from the 340 driver to the 390 driver and it seems to be working fine.