Holo blue theme has been downloaded and installed by over 1M users and the latest release is dated Oct 17, 2018. Adverts are a part of this application. Samsung and HTC users like the app.
A free .apk installation package of Holo blue theme 1.11.102E can be downloaded from Droid Informer and you can have a look at users' reviews on this site. Prepare 4 MB of free space on your device for this app setup package and keep in mind that it runs on Android 4.0 and above.
As users see it, you can experience the strong points of the app that are a nice UI and constant updates.