I've been using openwrt 18.06.2 on my netgear dm200 with great success for some time now on a VDSL2 connection to the NBN here in Australia (FTTN).
My service provider requested that I enable SRA (seamless rate adaptation according to them) for the purposes of debugging some recent dropouts I've been experiencing but I'm having trouble figuring out if it's even a feature on openwrt and, if so, how to enable it.
I'm using version 10.0.0.61 of the firmware. Current dsl settings are: