Hello,
I have multiple PIs with Volumio. Just did a system update on an older Pi2B with the above mentioned wifi dongle from v3.179 to todays v3.198. Looks like v3.198 is missing the rtl8192eu wifi driver. Did a fresh install of v3.179 and the dongle works out of the box. On a fresh install of v3.198 it is not recognized, so it was not a problem during system upgrade.
Any idea how to fix? Would be important.