[Printing-architecture] driverless clients after cups upgrade and general qyestion about larger environment concepts

Hi,

I am new on this list and would like to bother you with a (maybe stupid question) right away :) 

I do run a 'large' environment with roughly 1.000 queues pointing to 500 printers, the current setup involves a lpd server as a backend talking to the printers and different cups servers for different departments offering the relevant share of the queues to the LINUX clients. 

I use the factory provided PPD files for the printers and lpadmin to install the printers on the cups server (with an lpd backend pointing to the lpd server) then poll-server <cups-server-of-this-department> directive in cups-browsed.conf on the LINUX client.

After a recent upgrade to CUPS 2.4.1 on the cups servers (coming from ubuntu 18.04- whatever cups version that was)  support for color printing stopped and on the clients desktops I recognize that the printers are visible but tagged as 'driverless' which is probably part of my problem (?)

Maybe the whole concept is also a bit ignorant towards the ideas of cups but for quite a while I did not really see the concept of a client-server model for larger entreprise installations that can not rely on browsing etc.  ? 

Any insight would be much appreciated ! 

Best
christoph