The HTC Buttefly runs Android 4.1 Jelly Bean and features the updated version 4+ of the HTC Sense UI. Unfortunately, once you turn on the Buttefly you'll have to dig deep to find the new Jelly Bean goodies. For the most part, Project Butter's optimizations and Google Now are all that remind you what version of the OS you are currently running.
At first glance, Sense has remained unchanged since the Jelly Bean update, but it's not quite so. For one, there are minor color swaps in various places (the volume slider is now light blue instead of green), the task manager app has been revamped, and some apps like the flashlight are slightly changed, but nothing too drastic.
Here's a quick video which highlights the most significant modifications:
HTC is famous for its deep customizations to the interface of the host OS and the latest version of Sense is no exception. Despite Sense 4+ being almost the same as the 4.0 version, it runs a lot smoother because of Project Butter, due in large part to the consistent 60fps of all UI animations.
The lockscreen remains unchanged - by default, it has four shortcuts and a ring at the bottom, all of which are customizable, but there's a catch - in order to change the apps that display on the lockscreen you need to manually change them from the homescreen dock. This can be inconvenient as you may want different docked homescreen apps and lockscreen shortcuts, and other manufacturers like LG offer this option, which is preferable. Otherwise you drag the ring towards the center of the screen to unlock the phone just like before, or to any of the shortcuts into the ring to unlock the phone and launch the corresponding app.
But that's not the end of it - the HTC Butterfly comes with nine different lockscreens preinstalled. You can access the others from the Personalize menu - a photo album, Friend Stream, Weather, Clock, Stocks, Productivity, People, Music or just a plain wallpaper.
The Productivity lockscreen lists the latest missed calls, texts, emails and scheduled events. People lets you pick a group form your phonebook and a rectangular grid of their contact images will pop up on the lockscreen. Grab one of them and drop them on the ring to view their details. You can have more than one page of contacts too.
Music gives you a mini music player on the lockscreen.
The homescreen has an auto-hiding indicator of which screen you're on and a dock with five shortcuts - the middle one is locked to the app drawer, while the other four can be customized as you please (you can even put a folder there, if four shortcuts isn't enough).
Leap view is still here - tap the home key (while on the default homescreen) or do a pinch gesture to zoom out (with an awesome animation) to display the thumbnails of all homescreen panes at once. Upon a press and hold you can drag to reposition the homescreen panes. A small house icon indicates the default homescreen, which cannot be changed, although its order can be moved around.
You can have as many as seven homescreens - and with the ample set of preloaded widgets (as well as the huge variety available at the Play store), you might want to keep all of them. In case you don't - you can delete the unneeded ones right from the Leap view.
The Personalize button is absent from the dock since Ice Cream Sandwich, but you can still find all of its functionality in the Settings or use the dedicated app within the app drawer.
The proprietary Scenes function is an essential part of Personalize - essentially five custom homescreen setups (Work, Travel, Social, Play and default). Each scene changes the wallpaper and the set of widgets. For instance, the Work scene has a stock ticker, while the Social offers a Twitter widget. Those can be customized, of course, and you can download and assign new ones.
Switching between scenes takes a couple of seconds, but they're a handy feature if you use your Butterfly as both work and personal phone.
HTC Sense has another customization option called Skins. Every skin changes the look and feel of most of the onscreen buttons, application screens, option menus, and other items. They also come with unique wallpaper each and use different colors for various UI elements.
The main menu has the typical grid layout, which is composed of horizontal pages with shortcuts sorted alphabetically. You can set different sorting options - alphabetical, most recent or oldest - but you can't rearrange them manually. There are Search and Play Store shortcuts along with a menu for some options.
The main menu has a tabbed layout similar to different Sense elements (such as the phonebook). There are three tabs available at the bottom - All apps, Frequent and Downloads. You can rearrange them or remove Frequent and Downloads if you don't use them.
The Personalize app also has Sound customizations - you can pick a Sound set or individual ringtone, notification and alarm sounds.
Adding widgets to the homescreen is done in similar fashion to ICS and is one of the less successful changes.
You press and hold on the homescreen and everything zooms out so that the homescreen panes are visible as thumbnails on the top row of the screen. You tap a homescreen to select it and then select a widget to add to it (or you can just drag the widget).
We're not thrilled with the widgets themselves. While HTC has done a great job making them stand out in both looks and functionality, it doesn't make sense for a widget do take up an entire homescreen panel on the Butterfly's big and pixel-dense screen. The fact that most Sense widgets cannot be resized adds to the problem.
There's a search option to speed things along or you can choose a widget from the dropdown menu and then select which size you like, but that still feels like an extra step-the old method of picking a widget and then picking the size (if any) seemed simpler.
Editing the homescreen is different from vanilla Android. You can tap and hold on a widget and you can drag across homescreen panes. While you're dragging a widget (or shortcut or whatever), two "buttons" appear at the top of the screen - Edit and Remove. You drop the widget on either button to perform the corresponding action.
Edit can be used to modify the settings of a widget - e.g. choose a different folder for the Photo Frame album or choose a different version of the Clock widget. This saves you the trouble of first deleting a widget and then putting it on the screen again to choose a different version, setting and so on. The Remove option does as advertised.
The notification area gives you a Settings shortcut here if you need to power something on or off. There's also a Clear button to dismiss all notification or you can swipe them off one by one.
There is just one toggle here which is new to the notification area - the Power Saver on/off switch. It does exactly what it's supposed to do - toggles the power saving mode or (if you tap on its name) takes you to the Power Saver options. If the phone detects headphones it will also display the Beats Audio on/off switch in the notification area. The notification area is also available in the lockscreen.
HTC has remodeled the app switching interface - screenshots are displayed of the running apps, turned slightly to the side. They're ordered horizontally (instead of vertically as is the ICS standard) and you can swipe up to remove them. The not so-good news is that you can only see three of them at a time, even in landscape mode - a waste of screen estate. There's also no way to close all apps with one button, unlike on recent builds by Sony, Samsung, LG and others, which let you do that.
You get the slightly revamped task manager too. The only change is in the UI itself while functionality remains the same. It's simple to use - each running app is listed with an indication of how much RAM it's using (no CPU usage reading though). You can terminate apps one by one and there's a Kill All button too.