A "Premium APK" is a modified (modded) version of the official Spotify Android app. In these versions, third-party developers tamper with the original code to bypass the restrictions of the free tier.
The ability to skip any song at any time, bypassing the hourly limit on free accounts. Spotify Premium Apk 8.7.78.373 İndir – Orijinal
Removal of audio and visual interruptions between tracks. A "Premium APK" is a modified (modded) version