This update is available on Android for now, it will shortly come to iOS version, too.
"This powerful tool allows you to almost never hit the chain, whatever your use case is on Lightning (yes, even if it's mostly receiving). Very useful to navigate the high seas of current on-chain fees!"
"We have also added a visualization of your current inbound liquidity in the channel details:
Request inbound liquidity from your peer. "If you keep receiving funds over Lightning, you'll consume your inbound liquidity fast and may end up having to splice-in every incoming LN payments, which can be expensive because each splice is an on-chain transaction."
"By requesting liquidity from the peer, you can plan ahead and avoid future on-chain fees. This is now supported in Phoenix starting from 2.1.0, thanks to liquidity-ads (a new feature in the Lightning protocol)."
"Requesting liquidity is done manually (for now at least). A button to the liquidity screen has been added in the Home screen. Your inbound liquidity is also displayed in the channels view."