We got this unit installed at a remote site using solar and could issue health command and get Voltage info we upgraded to the latest OS from Mikrotik Website 6.27. Now the unit does not have the HEALTH option in winbox or web GUI?
Are you absolutely sure about this? I just tried logging into 2 RB2011iL routers that we have in production: one running 6.1, and one running 6.5 (so, both of which are older than the 6.9 you upgraded from). Neither one provides health information. (The 6.5 router does show a Health menu in Winbox, but shows a Voltage of 0.0.)
If you look at the
product page for the RB2011iL, you can see that it shows "Voltage Monitor: No" in the specs list. I am certain that the only 2011 models that have voltage and CPU temp monitors are the UAS/UiAS models. None of the L/LS/iL/iLS models ever did.
So is it possible that you have a 2011UiAS at your site, and not a 2011iL? If you have an iL, I'm not sure how it ever worked for you. You could certainly try downgrading to 6.9 again...it's fairly easy. Maybe you have a rare iL board that somehow has voltage monitoring, and later versions of RouterOS just assume that all iL boards don't have it? (Very unlikely, but I'm grasping at straws...)
-- Nathan