Is it possible to get somewhere laser DL445 Vectric postprocessor?

It came with the multi-installer for myself.
I suggest you contact your stepcraft vendor who should be able to send you the most up-to-date post processor. That is always the best route.

I have uploaded a copy of the postprocessors that I have - they may be old. A quick look didn't show any comments prohibiting redistribution.

Cheers