We are discontinuing development of the Online Piano Atlas app for Android devices! But good news: 

We are discontinuing the development of the Android application, but for those who use Android devices, we are offering a significantly superior alternative. They can then utilise the Piano Age Calculator web application, which is accessible not only on Android phones but also on any browser-enabled device (computer, tablet, laptop, etc.). The web application is compatible with all layouts, allowing for perfect mobile usage.
 

What to do if you have an Online Piano Atlas subscription and an Android phone? You have the option to change it at any time, or you can continue to use the Online Piano Atlas phone application until the expiration of your subscription, at which point you can switch to the Piano Age Calculator, accessible via this website; to do so, you must select a plan and continue to use the web application. IMPORTANT: please cancel your Online Piano Atlas phone app subscription before switching to the Piano Age Calculator web version. Here's how to do it: https://support.onlinepianoatlas.com/#Cancel

TIP: you may quickly add a website shortcut on your phone's homescreen that opens the web app instantly, eliminating the need to enter a web address to access the atlas. Here's a video guide on how to do it.