For some iPhone players, it may also come with a phone that suddenly believes it has been transported directly to the Burning Hells.
Several fresh iOS bug reports have appeared following the game's latest engine preparations, including complaints about severe UI flickering, incorrectly scaled interfaces, black screens and one iPhone 17 reportedly reaching around 40°C after 30 minutes of gameplay.
That does not mean the engine update is breaking every Apple device.
Far from it.
These are individual player reports, and Blizzard has not confirmed that they all share the same cause.
But the timing is interesting because Diablo Immortal has just begun rolling out the technology behind its major September engine upgrade.
And at least some players say their problems began immediately afterward.
One iPhone 17 Player Says the Phone Heats Up Within Three Minutes
One of the clearest reports comes from an owner of a regular iPhone 17 running iOS 26.6.1.
The player says their phone previously became slightly warm while playing Diablo Immortal.
After the recent engine update, they say that changed dramatically.
According to the report, the device now becomes noticeably hot in less than three minutes after launching the game.
And this is not happening with every graphics slider pushed upward in an attempt to recreate a desktop GPU benchmark.
The player says they are using Low Quality Mode.
After approximately 30 minutes of gameplay, they measured the outside of the phone at roughly 40°C.
Closing Diablo Immortal reportedly causes it to begin cooling again almost immediately.
The player also updated to the latest iOS version without solving the problem.
Their request to Blizzard is fairly straightforward:
Investigate CPU and GPU load after the engine update.
Another iPhone Is Having Severe UI Flickering
A separate report posted at almost the same time comes from an iPhone 15 Pro user.
That issue is graphical rather than thermal.
The player describes severe UI rendering and flickering after the latest update.
Interestingly, they say the actual 3D game world can look completely normal while standing still.
The interface is the part that starts behaving strangely.
That distinction matters because it suggests this may not simply be a case of the phone failing to render Diablo Immortal's entire scene.
The problem may involve specific interface or compositing layers.
Another forum contributor noted that a similar issue had apparently also been reported on Android through the community Discord.
Again, that does not establish a shared technical cause.
But it makes the problem worth watching beyond one particular iPhone model.
iPads Are Reporting Scaling Problems Too
And the iPhone reports are not appearing in isolation.
An iPad Pro 13-inch with an M5 chip has also been reported as suffering serious UI and rendering problems.
That player describes several symptoms:
- Chaos Convoy buff screens becoming almost completely black
- UI elements suddenly becoming massively enlarged
- Interface elements extending outside the visible screen
- Battle Pass and Activities menus appearing incorrectly positioned
- The 3D game world continuing to render while the UI itself becomes corrupted
The player says they attempted the usual collection of modern troubleshooting rituals:
Repair the client.
Restart the game.
Restart the device.
Update iPadOS.
Disable Game Mode.
Change multitasking settings.
Nothing permanently resolved it.
Another iPad owner later replied that they were seeing similar behaviour, including freezing when attempting to use chat.
The Engine Upgrade Is Still in Its Early Rollout
This is where the situation becomes slightly confusing.
Blizzard's official wording says Diablo Immortal's major engine upgrade arrives in September.
However, players have been able to begin updating the underlying engine in advance since August 24.
Blizzard is actually rewarding players for doing so.
Complete the early engine update and each character can claim 10 Legendary Crests.
We covered that unusual incentive when Blizzard first announced the Diablo Immortal engine upgrade and its ten free Legendary Crest reward.
The important detail is that Blizzard says the full visual improvements will not officially activate until the major September update.
So what players are downloading now is partly preparation for what is coming.
The September Upgrade Is Supposed to Improve Visuals
When fully released, the new engine technology is supposed to improve quite a lot.
Blizzard says it will:
- Rework visual effects for nearly 100 affixes
- Improve lighting and shadows in more than 10 environments
- Reduce excessive lighting effects
- Optimize ground materials
- Optimize water materials
Those sound like sensible improvements.
Diablo Immortal has accumulated four years of visual effects, cosmetics, wings and increasingly elaborate skills.
At some point, the screen begins to resemble somebody emptied a fireworks warehouse directly into Westmarch.
Reducing unnecessary effects while modernizing lighting could genuinely improve both readability and performance.
But engine changes are also exactly the sort of update that can expose device-specific problems.
Blizzard Has Not Confirmed the Engine Is Responsible
This needs to be stressed.
The iPhone 17 player specifically says their overheating began after the engine update.
The iPhone 15 Pro player says their severe flickering appeared after the latest Diablo Immortal update.
Other Apple users are reporting UI scaling and rendering bugs during roughly the same period.
That is useful evidence of a possible problem.
It is not proof of the underlying cause.
Blizzard has not published a technical explanation tying these reports directly to the new engine.
The iPhone 17 overheating case could theoretically be device-specific.
The UI problems could involve iOS or iPadOS compatibility.
Multiple bugs may have arrived in the same client patch for completely different reasons.
Right now, what we have are symptoms.
Not a diagnosis.
Forty Degrees Sounds Dramatic — But Context Matters
The temperature report also needs some perspective.
Phones become hot under sustained gaming workloads.
That is normal.
Diablo Immortal is a demanding 3D game constantly rendering effects, enemies, UI elements and network activity.
An exterior temperature around 40°C does not automatically mean an iPhone is being damaged.
Modern devices have thermal protections and will reduce performance if necessary.
The interesting part of this report is instead the change in behaviour.
The player says the same phone only became mildly warm before the update and now heats significantly even on Low settings.
If that before-and-after comparison is accurate, it suggests something worth investigating.
This Is Exactly Why Blizzard Is Rolling the Engine Out Early
There is another way of looking at the reports.
Finding these problems now is considerably better than discovering them after the September update becomes mandatory.
Blizzard has said that once the new engine officially launches, devices without the updated version will no longer be able to run Diablo Immortal.
That makes compatibility testing important.
The early rollout gives Blizzard several weeks of real-world data across an enormous variety of hardware.
iPhones.
iPads.
Android devices.
Gaming phones.
Old phones being held together by optimism.
If certain devices have rendering or thermal regressions, this is the period when Blizzard needs to find them.
The Free Legendary Crests Suddenly Look Like Hazard Pay
Blizzard's ten-Crest reward already seemed unusually generous for what is essentially an engine migration.
Now it looks slightly funnier.
Update early.
Test the new technology.
Receive ten Legendary Crests.
Report whether your interface has become enormous and pink.
Obviously that is not how Blizzard described the event.
But large-scale live games increasingly rely on millions of different hardware combinations doing things internal testing could never reproduce.
Mobile games have this problem more than most.
An update that behaves perfectly on one iPhone generation can do something completely different on another.
Most Players Are Not Reporting Disaster
It is also worth keeping the scale in perspective.
The Diablo Immortal forums are not currently filled with thousands of iPhone owners reporting melting devices.
These are relatively small bug threads.
Many players appear to have completed the early update without experiencing anything dramatic.
So this should not be read as:
The Diablo Immortal engine update is broken on iOS.
We do not have evidence for that.
The more accurate conclusion is:
Some Apple users are reporting new thermal and rendering issues after the latest update, and the timing overlaps with Diablo Immortal's engine migration.
September Is the Real Test
The full engine improvements arrive with Diablo Immortal's major September update.
That is when the visual overhaul becomes much more significant.
Before then, Blizzard has a useful window to investigate reports like these.
The goal of an engine upgrade is fairly straightforward.
Better visuals.
Better lighting.
Better materials.
Cleaner effects.
Ideally without turning the player's phone into a pocket-sized Hellforge.
The ten Legendary Crests are nice.
But most players would probably also like their UI to remain attached to the correct part of the screen.
Sources
Blizzard: Diablo Immortal Engine Upgrade and Early Update Rewards
Diablo Immortal Forums: iPhone 17 Overheating After Engine Update
Diablo Immortal Forums: iPhone 15 Pro UI Flickering Report
Diablo Immortal Forums: iPad Pro UI Scaling and Black Screen Report
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