Several pools prefer that the #xnsub (extranonce.subscribe) option be enabled on your miners. Nicehash and zpool are two that come to mind.

I have Antminer L3s and S9s that allow me to enable this option. The S9 doesn't require any extra config and the L3s require that I add "/#xnsub" to the end of the stratum URL after port number. However, the Avalons that I have don't seem to support #xnsub no matter what. I've tried "url:port#xnsub" and url:port/#xnsub" and neither enable the use of xnsub on any pool I've tried. At one point, Nicehash put out a special build of the Avalon controller firmware that supported it, however, it's really old code now and only works on ver 1 & 2 controllers. I have the latest firmware running on the Avalon controller (ver 3).

TL;DR - Anyone know how to enable #xnsub for an Avalon controller (ver 3)?

Thanks