There are many different apps available to smartphone owners which allow communication through voice, chat, and video calls, and Skype is one of those apps. While the app is certainly quite well-rounded compared to past versions, there was still some features missing that likely made it feel like a step behind some of the other communication apps out there to some users. This would be the ability to interact with the app from the notifications. In Skype's latest update, they've opened up this capability which should make it more easy and convenient for users to engage with each other quickly and on the fly.
In Skype version 5.11, Microsoft has added heads up notifications to the app, so for users on Lollipop when they get a Skype call or message, they'll see the heads up notification pop up on screen if they're already doing something else, and it brings in options to allow a person to call their contact back or reply with a message. Users will get the same type of interaction options from the original notification which pops up in the notification pull down panel so if your screen is locked and asleep when you get an incoming Skype message or call, you can simply wake the display and reply or call back from here too.
Other minor changes include a new status bar icon for the app which most users probably won't notice since it poses no functional purpose. While being able to reply straight from the notification panel or from the heads up notification is easy and make things more convenient, tapping on this option will open up the Skype app so replies can't be done entirely from the notification itself. Some might see this as a slightly pointless update then, but on the contrary it helps shave off a few seconds as well as the task of having to first open up the Skype app, find the contact you want to reply to or call and then initiate one of those things. The app update should be live in the Play Store as of now and users who are already using Skype can likely head to the "my apps" section to start the update.