Sony's long-awaited life-tracking app, Lifelog, hit Google Play on Wednesday--and this should be good news for anyone who's already purchased Sony's SmartBand wearable, which requires Lifelog and a Sony host app to work.

But for now it appears that the SmartBand and its mission-critical Lifelog app are only optimized to pair with a single smartphone, the yet-to-be-released Xperia Z2. What's more, compatibility of any type seems limited to Xperia phones running Android 4.4 and higher, according to the app's description on Google Play.

That could be bad news for people who don't own these Sony phones, but already purchased the SmartBand from Amazon (where it's no longer for sale) or might still buy the wearable from Newegg.

I was one of the original Amazon consumers, and purchased the SmartBand for $99--a far cry cheaper than the $140 Newegg is charging. The product packaging has an Android 4.4 label on it, but doesn't mention specific hardware requirements. Nor are any compatibility warnings listed on the two retail websites. Yet when I tried to download the essential Lifelog app to both an HTC One (M7) and a new Samsung Galaxy S5 (both Android 4.4 devices), my efforts yielded only the heartbreak of defeat.

So now it looks like the SmartBand will have only Sony-exclusive hardware support for the time being. This would be a new development for Sony's wearables effort, as the Smartwatch 2 works with any Android phone running 4.0 or higher. I have an email out to Sony asking for clarification, but for now it looks like ultra-early-adopting, Sony phone have-nots like myself are stuck holding a SmartBand that can't actually work.

In case you're wondering what all the hubbub is about, check out the Lifelog video. Both the app and the SmartBand look to offer a fresh new take on activity-tracking, letting users record social media events, entertainment events and other lifestyle data to a graphically lush timeline.