When the HTC One M9 was announced back in March in Barcelona, it came with a new version of Sense. Sense 7. Which happens every year, actually. However, while some of HTC's competitors don't usually update their older smartphones to the newer version of their UI (especially Samsung), HTC does update their older devices. While the HTC One M8 was updated to Lollipop already, there's another update headed to owners of the One M8 in August which will bring Sense 7 to One M8 users. Additionally, the update will bring Android 5.1 to those users. Which isn't a huge update over Android 5.0.2, but it does fix a number of bugs. So it's still a pretty important update.
The update to Sense 7 isn't really that drastic, there are still quite a few new features that are included, like HTC's new Theme engine. Which they are very proud of and should be. Their theme engine is pretty robust, where you can select an image and create a theme from that image. You can even go a step further and create your own theme from scratch, using their Photoshop template. There are a number of other features available with the Sense 7 update as well. Which includes the updated Blinkfeed, as well as many others. Although a number of the features are now baked into HTC's apps which are now in the Google Play Store.
While August is still quite a ways off – the update is likely slated for that time to give the HTC One M9 a bit more time to sell – it is still nice that owners of last year's flagship will get this year's software. Something you don't see too often from these manufacturers. While this was HTC UK that confirmed the August time-frame, I'd doubt that the US would see Sense 7 on the HTC One M8 ahead of that time. Europe and even Asia usually get software updates before us, and additionally, the US has carriers that want to approve updates first before they send them out to their users. Which takes extra time. I'd venture to guess that we'll see the update later on in the fall here in the US.