After updating to version 8.3 the Sonos app rapidly drains the battery on an iPhone SE running iOS 11.2.5 (42% of all battery usage in the last 24 hours, overall to cca 40%, so 25% of battery capacity goes just for Sonos used for 4 minutes foreground and 1 minute background (!)). Lock screen controls is Off (since this was suggested as a possible cause in a number of places). I have also tried deleting and reinstalling the app: same behaviour. Before the update Sonos battery usage was only a few percent. Nothing else has changed.
I uploaded the diagnostics 8420376. Sonos "solution" has been very helpful:
"We have been investigating reports from customers who are perceiving high battery usage by the Sonos app on their iOS 10 devices. The data has now been analysed and we have determined the battery usage to be reading as expected.
Our only advice to customers who do not agree with this is to force stop the app when it is not in use."