iOS: the current version of iReal Pro requires iOS 11.4 or later.
App size: approx. 78 MB
OS X: the minimum OS X you need in order to run the latest iReal Pro is 10.11 or later. You can purchase a previous version of the app for 10.6.8 & up. (for Mac computers with minimum 64-bit processor) though our website: https://www.irealpro.com/#mac
App size: approx. 53 MB
Android: the latest version of iReal Pro requires OS 6.0, iReal Pro 8.0 requires OS 4.4 or up. If you purchased the app previously and need to install it on a device with older OS version, contact us through the support form with the email address you used for the original purchase in Google Play Store. (minimum OS 2.2. and Armv7 Processor)
App size: approx. 45 MB
You need 5 - 20 MB to have thousands of songs in the app.