We have received tips that a new firmware update for the Lumia 550 is currently rolling out, but it apparently does not add the "Double Tap to Wake" feature that has been included in previous firmware updates for the Lumia 650, 950 and 950 XL phones.
It's possible that the budget-price Lumia 550 simply cannot support the Double Tap to Wake features for this new firmware. Hopefully, Microsoft will offer some more information on how this update differs for this phone compared to its other Windows 10 Mobile products. If you own the Lumia 550 and have received the update, let us know what differences you have noticed in the comments!
To see if your unlocked Lumia 550 is getting this update, go to Settings > Update & security > Phone update > Check for updates. If eligible you will see MICROSOFTMDG update.
Thanks again to our readers for their tips via emails and forum posts!