You might wonder why anyone would go through the hassle of sideloading an IPA instead of just downloading the free current version from the App Store. Here are the main drivers.
Modern GarageBand consumes over 1.5GB of storage and can slow down older A-series chips. Version 1.4.1 is roughly 450MB and runs butter-smooth on an A5 processor (iPad 2). For musicians who just need a four-track recorder with virtual drums, the older version is faster, simpler, and less distracting. garageband 1.4.1 ipa