The Galaxy S8 and Galaxy S8+ smartphones that were launched this year are the first devices by Samsung to feature Infinity Display design. The South Korean company has also brought the Infinity Display design to the newly unveiled Galaxy A8 (2018) and Galaxy A8+ (2018) phones. Various features such as support for 18.5:9 aspect ratio and rear-mounted fingerprint scanner that are available on the Galaxy S8 duo are also available on the A8 (2018) and A8+ (2018) phones. However, unlike the S8 phones, the A8 (2018) duo lack pressure-sensitive display area at the lower side of the screen that functions as a physical home button.
Since the pressure-sensitive home button is not available on the Galaxy A8 (2018) and Galaxy A8+ (2018) smartphones, these phones cannot be unlocked by long pressing on the home button. Hence, users will be able to unlock these phones by pressing the power button.
Users can also unlock the A8 duo by tapping twice on the display for waking up the device since the the Always-On Display (AOD) feature comes enabled on these phones. The other way to unlock the A8 (2018) or A8+ (2018) is by using the fingerprint sensor located the backside of the phone.
There is no official confirmation on why the company decided to axe the pressure-sensitive home button feature on the Galaxy A8 (2018) and Galaxy A8+ (2018). It could be a cost cutting move by the company to make the high-end feature available on flagship phones such as Galaxy S8, Galaxy S8+ and Galaxy Note 8.