Confusing with nvidia long lived branch releases


I have Nvidia Quadro K2100M

and I had the long lived branch 440.100, it was work well with my machine (it work with NVEC encoder),
after that I upgraded to long lived branch 450.66 which doesn’t run NVEC encoder

My Questions are:

  1. when read 440.100 supported products I didn’t find my card in supported, but also it work well with this driver, is there different source to see supported products for nvidia drivers ?

  2. if the previous long lived branch (440.100) work well with card, why the next long lived (450.66) doesn’t work ?