Some previous versions of MCPE have behaved very well on 512MB iPads, such as the iPad mini 1st Gen (which both my kids use), even when playing local multiplayer games for long periods of time. However, recent versions, including 1.2.3, have increased memory usage, which causes memory thrashing (which the kids observe as severe lagginess) and jetsam-triggered terminations of MCPE (which is obviously highly disappointing).

You can see from the JetsamEvent logs that are produced during these situations:

• "largestProcess" : "minecraftpe"
• "rpages" (resident pages) for minecraftpe around 65000-70000 pages, or 260-280 MB (32-bit iPads all use 4K pages).
• for the JetsamEvents in which minecraftpe is terminated by iOS, it will show "reason" : "vm-pageshortage"

If I launch MCPE on two iPad mini 1s, open a world in one, and join the game from the other, it will almost immediately jetsam the MCPE on the first iPad. But a short period of playing will also make it jetsam too.

In order to remedy this, it will be necessary to reduce the memory footprint on these devices. That optimisation may not be needed on 1GB and larger units.

You can query a device's total RAM by calling [NSProcessInfo processInfo].physicalMemory.

Please, have your QA team make it a standard practice to exercise 512MB iPads prior to release.