: Useful for merging base games, updates, and backports into a single, easy-to-install PKG file.

: Historically, Sony offered a Digital Upgrade Programme where owning a PS3 disc allowed you to download a PS4-compatible digital version (PKG) of the same game for a small fee. 3. Creating and Managing PKG Files

The PS3 used the complex , while the PS4 uses x86-64 architecture . Because of this, you cannot simply rename a .pkg file from one console and expect it to work on another. Most "conversions" you see online are either specific remasters (official) or emulated environments (unofficial). 2. How PS3 Games are Run on PS4 (Jailbroken Systems)