With major design changes Android 5.0, not Android 4.5 is likely to be the future build of Android.
The Android 5.0 release date might happen as soon as Google I/O, according to latest news and hints that suggest that the upcoming Android OS is just right around the corner.
One of the hints that point to the imminent release of the Android 5.0 is a screenshot posted by Google itself showing the time. Moreover, a Quantum Paper is released via the Android Police, which gives information about the plan of Google to create a major redesign called "Android L."
Although the screenshot may not necessarily indicate the existence of the Android OS, the time indicated hints at it. In the past, before the release of the Android 4.3, we have seen 4:30 p.m., before the release of the Android 4.4 KitKat we have seen 4:40 p.m. Basically, it has been the tradition of Google since the launch of the Android 2.3. Now, Google tweeted about the new World Cup feature along with an image of several Nexus 5 that displays a time of 5:00 p.m.
The tweet from Google reads, "Get the latest #WorldCup match scores and schedules with Google Now on iOS and @Android http://goo.gl/4OwgqZ."
As such, it is safe to infer that there will be no Android 4.5 coming; instead a major change will come with the Android 5.0, which is currently rumoured to be named Lollipop.
According to Android Police, Quantum Paper is the primary name for a fresh and unified design framework made to offer experiences consistent across all platforms. It represents Google's effort to create and encourage beautiful and consistent designs that delights across all platforms. It is an ambitious project, which aims to unify and codify paradigms for visual, interaction and motion design across the Web, iOS and Android.
Basically, it will be a major revamp of the Android interface, which makes sense to have a launch at the Google I/O 2014. With the event just around the corner on June 25 and June 26, the Android 5.0 or "Android L" might be seen very soon.