Of all the features to come to Android with the 6.0 update, Doze is easily the most discussed. Some love it, claiming massive strides in battery performance during the day. Others aren't quite so pleased with the service, and complaints of missed messages and third-party app features breaking are often cited as why. Based on our own testing here at Android Central, we can tell you Doze is far from perfect. While the battery optimization when you aren't using your phone is clearly there, there are occasions where phones drift into Doze when they shouldn't and messages don't arrive until the phone wakes back up.
These concerns prompted one member of our forums to ask what happens to the more important features in Android, specifically Android Device Manager, when Doze is doing its thing.
If you've set your phone down somewhere and walked away for a couple of hours — yes, some people put their phones down on purpose for multiple hours at a time... on purpose — will Android Device Manager be able to locate the phone and perform all of the functions offered by the service? It's an important question, especially when you consider Device Manager can locate, ring, and factory reset your phone from an app or website if you can't find it. If Doze has forced everything quiet to save power, will this feature still work?
The short answer is yes. Doze is designed to allow apps and services that are deemed "High Priority" to always be able to communicate, which is why you still get phone calls and text messages from your carrier. Any app that isn't a critical cellular app, but wants to be considered "High Priority" uses Google Cloud Messaging so Google can monitor how often it pings your phone to ensure these apps aren't keeping your phone awake for no reason. Android Device Manager uses both cellular and Google Cloud Messaging services to function as location and ring push services, so there should never be a point in which this feature is unavailable due to Doze.
That having been said, software is imperfect and sometimes things break. The easiest way to test that Doze is functioning correctly for Device Manager is to use the service and take a look for yourself. Leave your phone somewhere with no motion that isn't connected to power, and after an hour or two look for the phone on Device Manager. The web interface gives you the last time the phone was located, and if everything is working correctly that time should be within a minute of your current time. If your phone can be located by the service, everything is working as intended. If that's not happening, there's a problem worth reporting.