Once you have downloaded your IPAs, copy them to a USB drive or cloud storage. Apple could shut down the legacy store endpoints at any time.
Do not install 12.6.3 on your main modern PC if you also use Apple Music streaming or need iOS 18/19 device backups. Instead, keep it on an old laptop or a virtual machine dedicated to app archiving.
If you have been using iTunes for more than a few years, you have likely noticed that Apple removed one of its most practical features: the ability to download and manage iOS apps (.IPA files) directly on your computer.
Since iTunes 12.7 (released in September 2017), Apple officially killed the App Store within iTunes. However, is the last version that still contains the full, functional iOS App Store.
For most users, the modern Finder (Mac) or Apple Devices app (Windows) is superior. But for the niche task of , iTunes 12.6.3 remains the last official tool Apple ever made.