because Phonesky resides in /system/priv-app or /product/priv-app . Without root, you cannot overwrite it. A standard user install of a different com.android.vending APK will fail due to signature mismatch.
: On March 6, 2012, Google consolidated its fragmented services—Android Market, Google Music, and Google eBookstore—into one unified platform: Google Play . Play Store Phonesky Apk--
Sometimes, a new Play Store update introduces bugs. By downloading an older version of Phonesky.apk from a trusted archive, you can roll back to a more stable release. Conversely, you might want the latest beta version before it rolls out in your region. Google consolidated its fragmented services—Android Market