The full reveal of the G5 is expected on Feb. 21, just prior to the start of Mobile World Congress in Barcelona.
LG hasn't given many other hints about the G5, although it tagged an animation on the Facebook page with the line, "Never go asleep while others do."
The G5 is also rumored to have a removable battery that is pulled out from the bottom of the phone. LG's invitation to its Feb. 21 event includes the words "play begins" and a picture of a jack-in-the-box toy, leading some analysts to conjecture that the G5 will focus heavily on gaming uses.
How LG markets and advertises the G5 could be a sign of growing recognition by vendors that smartphone growth is slowing. As a result, vendors will attempt to draw attention to new features that are relatively minor compared to past years. Many smartphone users need a bigger incentive to upgrade than an always-on display, one analyst said.
"Android unit shipments and revenue growth are slowing year-to-year, and with news like [an always on display], it's clear [LG] is getting a little antsy about what 2016 has in store," said Jack Narcotta, an analyst at TBR.
He said that an always-on display isn't much different from LG's previous Glance View or even the Motorola Moto X with its gesture-based features.
"From the user's perspective, always-on is a quirky feature that will have a niche audience, at best," he said. "Is it really that much of a distraction or effort or waste of time to press a button the side, top or bottom of your phone to see what you've missed"
Narcotta said that Android by default presents a lot of notifications from apps and services on the home screen. "Are you sure you want that cluttering up the screen and interfering with your daily routine" he asked.
Both Apple and Samsung last month predicted slow sales of smartphones and mobile phones in early 2016. The market for smartphones is saturated in developed countries, and customers keep their smartphones longer, not seeing a significant reason to upgrade.
Samsung, the leader in global smartphone shipments in 2015 with 23%, was followed by Apple (16%), Huawei (7%), Lenovo (5%) and Xiaomi (5%), according to IDC. LG has struggled to reach the top five in rankings.
At Mobile World Congress, along with LG, both Samsung and Huawei are expected to announce new flagship phones, with Samsung expected to unveil its next Galaxy S7 and S7 Edge.
"There are simply too many less expensive and nearly as capable alternatives in the Android market to justify making a big leap back into the premium Android phone space," Narcotta said. "Of course, LG, Samsung, Huawei and others will release new flagship models, but the bulk of their business will come from mid-range and entry-level devices."
Patrick Moorhead, an analyst at Moor Insights & Strategy said that as LG and other smartphone vendors find ways to distinguish themselves from competitors, a true always-on feature "could come into play." In the past, both the Moto X and the LG Glance View have rapid ways to see information on the home screen, but nothing yet has left the display on without touching the display or moving it a certain way.
"A truly always-on feature could be perceived positively, but it needs to be marketed effectively, and LG hasn't yet invested enough in the U.S. to market its current features," Moorhead said.
LG also hasn't indicated what always-on will mean for sapping battery power, a concern that buyers will surely have, analysts said.