It seems Google is making the rounds with an updated search bar inside of the Google Play Music application on Android devices, making it so that users will have the same relevant options when tapping the search like before, but with a new look that is more uniform with other Google apps. This doesn't seem to be an update to the app at all so it's likely a server side switch that Google is enabling, which means any users who aren't seeing the changes now will just have to wait until those changes come in, since it isn't an app update though it shouldn't be too long before users notice the swap, also, some users have likely been working with this new search bar in Play Music for a little while, so perhaps now Google is just closing the gaps and getting everyone else the changes.
While there are no real changes to the functionality of the search as you can still have Google listen for audio to identify songs, something which was already capable using search in Play Music, the updated design changes shows that Google is looking to keep the visuals for even smaller elements like the search bar as up to date and in line with other services as possible.
As this is just a minor change to the look of one element within Play Music, there isn't a whole lot to be excited about here, but it's nice to see that Google is taking initiative in keeping even the small parts of the machine as up to date as they can. Aside from this tiny tweak to the search bar, Play Music has seen some other recent changes as Google finally launched the family plan for Play Music subscriptions towards the end of last year, which also brought about the capability for the Google Play Family groups, allowing users to share a payment method for buying apps, games and other content, while the Play Music Family plan allowed for everyone included to share Play Music subs for one low cost of $14.99 per month. Family plan groups can have up to six people, which made the subscription a huge savings if a family is full.