The Taiwanese company confirmed the news via its official ZenTalk forum and added that Android L updates for the ZenFone 4 (A400CG and A450CG), Asus ZenFone 5 (A500CG) and Asus ZenFone 6 (A600CG) have been sent for "final verification."
The ZenTalk post said, "Asus was scheduled to provide ZenFone 4, ZenFone 5, ZenFone 6, ZenFone5 LTE and PadFone S with Android L upgrade in the end of April. We've sent the new version for final verification and we expect to release the upgrade soon."
The company alongside also confirmed Android 5.0 Lollipop updates for the Asus ZenFone 5 LTE and Asus PadFone S. The ZenFone 5 LTE is likely to start receiving the update early May while the Asus PadFone S will get the update beginning June.
Some of the notable features of the Android 5.0 Lollipop version include a cleaner, flatter design with a more fluid interface and animations. There is a new 'Quick settings' menu that has been revamped, and includes new controls like flashlight, hotspot, cast screen controls and more. The lock screen now displays richer notifications, and users can view and respond to messages directly from the lock screen.
Asus initially confirmed the Android 5.0 Lollipop update for the ZenFone 4, ZenFone 5, and ZenFone 6 smartphones last year.
On Thursday, the ZenFone 2 series ahead of India availability started receiving its first FOTA (firmware over-the-air) update that added new features.