General GPIO handling today

I have a general question about how GPIO abstraction is used in openWRT nowadays.
The research i did shows that there is a deprecated way to talk to GPIO that is in the documentation of openWRT and i assume that this is outdated as i read in sysfs is deprecated.
Can somebody from the core dev Team take a look at the doc's and explain me how to use GPIO in recent openWRT 18.06 or 19.07? Maybe i can update the doc's after i understand what techniques are the right one to use nowaday.

The sysfs API is still available