Apple introduced Parts and Service History in iOS 15.2, and the system has kept evolving as Apple expands its repair verification and calibration requirements. iOS 27, released on September 14, 2026, is now the current major version of iOS.

This guide explains the rules Apple documents today, and what they mean for iPhone repair and refurbishment.

What does "Unknown Part"  mean?

After a repair, go to:

Settings › General › About › Parts and Service History

Depending on the iPhone model and its repair history, Apple may show one of several statuses next to a replaced component.

According to Apple's current support documentation, a component can show Unknown when it:

• isn't a genuine Apple part;
• isn't working as expected;
• hasn't completed Apple's verification or pairing process after the repair;
• has been modified, or otherwise can't be verified.

Note An Unknown Part message can also affect the device's trade-in value.

Does "Unknown Part" affect how iPhone works?

Not necessarily.

Apple states that messages in Parts and Service History generally don't affect your ability to use iPhone, unless the specific message says otherwise.

Repair status can still matter for specific features. For example, when a repair requires calibration and that process isn't finished, Apple says Face ID may not be available to unlock the device, authorize payments, or sign in to apps until calibration is complete.

So don't read an Unknown Part message as a hardware failure on its own. The questions that matter are whether the replacement component works as it should, and whether the required repair and calibration process can be completed.

How long does the Unknown Part notification last?

Apple's current support documentation says iPhone shows an Unknown Part notification:

• the first time the device is unlocked after the repair;
• again five days later.

The Unknown Part information also stays in Parts and Service History. The repair record remains part of the device information Apple maintains.

How to use Repair Assistant on iPhone

Apple's Repair Assistant is designed to finish supported repairs and calibrate supported replacement components on supported iPhone models.

Before you start

• Update iPhone to the latest available version of iOS.
• Connect iPhone to Wi-Fi.
• Make sure the device has enough battery power.
• Open Settings › General › About.
• Open Parts and Service History.
• Choose the component that shows Finish Repair.
• Follow the onscreen instructions to finish the repair.

Apple notes that this process doesn't support captive networks, or networks that require 802.1X authentication.

If Repair Assistant can't finish the repair, check the network connection, device software, battery level, component installation, and whether the required Apple Account information is available.

What changed with iOS 27?

iOS 27 was released on September 14, 2026. Apple's major iOS 27 update focuses on system improvements, Apple Intelligence, Siri, parental controls, performance, and other platform features.

For repair and refurbishment businesses, one change worth noting is Apple's updated Ready for Repair or Trade-In process.

In iOS 27 or later, Apple directs you to:

Find My › choose your device › More › Repair or Trade In › Enable

This workflow prepares a device for repair or trade-in. In many service situations it replaces the older practice of turning off Find My before a repair.

6. Parts and Service History in apple's current documentation

apple's current support documentation covers more component types than the original battery and display repair workflow. Depending on the iPhone model, Apple can provide repair-history information for components including:

• Battery
• Display
• Front camera
• Rear cameras
• Enclosure
• and more

The exact components available depend on the iPhone model.

That means a technician shouldn't judge a replacement part only by whether a display or battery shows Unknown. Check the full repair history, and the status of every serviced component.

What about third-party iPhone displays?

Three points matter most for aftermarket displays.

Functionality comes first

An Unknown status doesn't necessarily mean the display is faulty. apple's current documentation lists several possible causes, including a non-genuine part, a malfunction, incomplete verification or pairing, and modification.

Repair status matters

If the replacement is a genuine Apple component and the repair isn't finished, the device may show Finish Repair until Repair Assistant completes the required steps.

Check current iOS behavior before refurbishing at scale

Apple's repair verification and calibration system can change with future software releases. For shops that process large volumes of devices, it's worth testing replacement parts against the current version of iOS before placing a bulk order or starting a refurbishment run.

For repairs where the original front sensor flex is damaged or non-genuine, REWA Shop offers diagnostic-compatible iPhone displays with a front sensor flex — an additional aftermarket option for technicians who need to run diagnostics after a display replacement. Evaluate these displays the same way: display functionality, diagnostic results, iOS compatibility, and Parts and Service History.

What about third-party iPhone batteries?

The same principle applies to battery replacement. After installation, check:

Settings › General › About › Parts and Service History

Depending on the component and the repair process, a battery may show as Genuine, Used, Unknown, or another applicable repair status.

Apple also notes that Parts and Service History information is kept as part of the device information, and used for purposes that include safety analysis and improving Repair Assistant.

For refurbishment businesses, evaluate a battery replacement on:

• Battery functionality
• Battery health reporting
• Repair and calibration status
• Parts and Service History
• The current version of iOS
• Whether any required repair process can be completed

REWA Shop also offers diagnostic-compatible iPhone batteries designed for supported repair and diagnostic workflows, giving repair shop an additional aftermarket option when replacing an iPhone battery. Technicians should still check battery performance, system information, Parts and Service History, and compatibility with the current version of iOS.

iOS 27 Repair Checklist for Refurbishment

Before buying or installing third-party replacement parts, run through the following checks.

1. Confirm the iOS version: Test the part against the version of iOS currently installed on the target device.
2. Check Parts and Service History: Look for Genuine, Used, Unknown, Unverified, or Finish Repair.
3. Test every core function: For displays: touch, brightness, image quality, proximity sensor behavior, and related functions. For batteries: charging, battery health information, temperature, and power delivery.
4. Finish Repair Assistant when it applies: If the component shows Finish Repair and is supported on that iPhone model, follow apple's supported repair workflow.
5. Check the device before resale: Review Parts and Service History before handing a refurbished iPhone to a customer or listing it for resale.
6. Test current firmware before buying in bulk: Don't assume a component that worked on an earlier version of iOS will behave the same way after a major iOS update.

Frequently Asked Questions

Does an Unknown Part message mean iPhone is damaged?

No. An Unknown Part message means Apple can't verify the component through its current validation process. Apple lists several possible causes, including a non-genuine part, a malfunction, incomplete verification, or modification.

Can I remove an Unknown Part message?

It depends on the cause. Repair Assistant can complete supported repair and calibration steps, but a third-party component shouldn't be described as a genuine Apple part just because Repair Assistant was run.

Does an Unknown Part affect iPhone performance?

Not necessarily. Apple states that Parts and Service History messages generally don't affect how you use the device unless the message says otherwise. Individual repair or calibration issues can still affect specific features.

Can a used Apple display show “Used”?

Yes. Apple states that on iPhone 12 and later with iOS 18 or later, a display that has been used in, or installed in, another iPhone can show Used.

Does iOS 27 change the Parts and Service History system?

iOS 27 continues apple's repair verification and Parts and Service History framework, while adding device-management features such as Ready for Repair or Trade-In. Use apple's current support documentation as the reference for the latest supported repair workflow.

Should repair shops test parts after every major iOS update?

Yes. Apple can change repair, verification, calibration, and device-management behavior through software updates. For professional refurbishment, testing replacement parts against the current production version of iOS is a practical way to reduce unexpected compatibility issues.

Conclusion

An Unknown Part message after an iPhone repair doesn't necessarily mean the replacement component is defective.

Under apple's current iOS 27 documentation, the core concepts remain:

Parts and Service History → Finish Repair → Genuine / Used / Unknown / Unverified

For repair shops and refurbishment businesses, the most reliable approach is to evaluate hardware functionality and apple's current repair status together, rather than treating an Unknown Part message on its own as a failure.

As iOS continues to evolve, test replacement parts against the latest production firmware before committing to large-scale refurbishment or purchasing decisions.

The smartphone business is no longer defined only by new-device sales. Longer replacement cycles, higher device prices, refurbished phones and growing access to repair are creating a larger economic role for the aftermarket.

What is the smartphone aftermarket?

The smartphone aftermarket covers the products and services that keep devices in use after their original sale. It includes replacement screens and batteries, charging components, cameras and other spare parts, repair labor, refurbished and pre-owned phones, trade-ins, accessories and related services.

This distinction matters because the aftermarket is not one standardized market. A report about refurbished smartphone sales is measuring something different from a report about replacement parts or repair services. Market-size figures should therefore be compared only when their definitions, geography and revenue basis are the same.

Why new smartphone sales do not tell the whole story

Global smartphone shipments grew about 2% year over year in 2025, according to Counterpoint Research. Apple led the market with 20% shipment share, while Samsung held 19%.

The picture changed sharply in 2026. Counterpoint reported that global smartphone shipments fell 6% year over year in Q1 2026, and its May 2026 outlook forecast a 13.9% decline for the full year, to about 1.08 billion units. Memory-component shortages and higher component costs were major factors.

At the same time, premium phones remain economically important. Counterpoint reported that the global smartphone average selling price passed $400 for the first time in a quarter in Q4 2025, while smartphone revenue reached a record $143 billion for that quarter. Higher device values can make repair and refurbishment more attractive because owners have more value to preserve.

What this means for the aftermarket

• Slower new-device sales can increase the importance of keeping existing phones in service.
• Higher replacement costs can make repair a more attractive alternative.
• Premium devices create greater economic value for quality refurbishment and repair.
• Longer software support and durable hardware can extend the period in which parts and service are needed.

Repair parts are a major growth opportunity

The Business Research Company estimates that the global mobile device repair parts market will grow from $20.67 billion in 2025 to $23.45 billion in 2026, with a projected value of $39.18 billion by 2030. The report covers parts used for smartphones, tablets and other mobile devices, including displays, batteries, camera modules, connectors, buttons and speakers. These figures refer specifically to the mobile device repair parts market; they should not be presented as the size of the entire smartphone aftermarket.

Why repair parts demand is increasing

• Higher device prices: Expensive phones can justify repair instead of replacement.
• Longer ownership: Consumers are keeping devices for longer, creating more opportunities for battery, display and other repairs.
• Online parts availability: Repair shops and technicians can source replacement components from a wide range of suppliers.
• Independent repair: More repair providers can access parts, documentation and diagnostic resources.
• Repair regulation: New rules in some markets are increasing the availability of spare parts and repair information.

The quality question is becoming more important

A larger parts market does not automatically mean that every replacement part is equivalent. Displays, batteries, cameras and other components can vary in materials, calibration, compatibility, reliability and warranty support.

For repair businesses, the practical opportunity is therefore not simply to sell more parts. It is to reduce repeat repairs, improve first-time repair success and make part quality easier for technicians to evaluate.

Refurbished smartphones and the secondary market

Refurbishment is another important part of the mobile aftermarket. Counterpoint Research reports that global refurbished smartphone sales grew 5% in 2024. Apple accounted for 56% of refurbished smartphone sales that year, up from 51% in 2023.

Growth moderated in the first half of 2025: global refurbished smartphone sales increased 3% year-over-year. Counterpoint reported strong performance in emerging markets, while several mature markets were broadly flat. Apple remained particularly strong, with refurbished iPhone sales increasing 7% year over year in H1 2025.

More recent regional data show that affordability continues to support refurbishment. In India, refurbished smartphone volumes increased 13% year over year in H1 2026 while new smartphone volumes fell around 11%, according to Counterpoint Research.

Why refurbishment supports the repair ecosystem

A refurbished phone often passes through inspection, testing, repair, parts replacement and quality grading before resale. That creates demand for the same repair skills and components used by service shops, while also creating a second revenue opportunity for businesses that can combine repair and refurbishment.

Right-to-repair is changing parts availability

Regulation is becoming one of the clearest structural changes in the repair market. In the European Union, ecodesign requirements for smartphones and slate tablets placed on the EU market have applied since June 20, 2025.

The European Commission says the rules include requirements covering repair and disassembly, spare-part availability and software support. Critical spare parts must be available to professional repairers within 5–10 working days and for seven years after the end of placement of the product model on the EU market. The rules also require non-discriminatory access for professional repairers to software or firmware needed for replacement work.

The EU framework also introduces a repairability score on the energy label. The policy direction is important because it makes repairability a product characteristic rather than only a service-market issue.

Apple and independent repair

Apple's Independent Repair Provider program gives qualifying businesses access to Apple genuine parts, tools, repair manuals, diagnostics and training for eligible out-of-warranty repairs. Apple does not publish a current universal count of IRP locations on the pages reviewed here, so older figures should not be presented as a current 2026 total.

Regional market differences

The aftermarket does not develop at the same pace everywhere.

North America

North America is a mature repair and refurbishment market with significant premium-device demand. The Business Research Company identifies North America as the largest region for the mobile device repair parts market in 2025. High device values, established service networks and strong online parts distribution support the market.

Asia-Pacific

Asia-Pacific is expected to be the fastest-growing region in the mobile device repair parts market according to the same market study. The region also contains very large smartphone markets with different repair models, from highly organized service networks to independent and informal repair businesses.

Europe

Europe is particularly important from a regulatory perspective. The EU's ecodesign rules make repairability, spare-parts access and software support increasingly relevant to manufacturers, repair providers and parts suppliers.

Emerging markets

Emerging markets can benefit from the affordability of used and refurbished premium phones. Counterpoint's India data from H1 2026 is a strong example: refurbished volumes grew while new-device volumes declined, showing how higher new-phone prices can redirect demand toward the secondary market.

What the market means for repair businesses and parts suppliers

1. Focus on repairable, high-value devices

Premium smartphones can support high-value repair transactions because the cost of preserving an existing device is lower than replacing it with a comparable new model.

2. Build around the parts technicians replace most

Displays, batteries, charging components, cameras and other common replacement categories should form the foundation of a practical parts catalog. The exact mix should be based on a supplier's own sales and repair data rather than unsupported global failure-rate percentages.

3. Make compatibility and quality easy to understand

Clear model compatibility, part specifications, testing standards, warranty terms and installation information can reduce purchasing uncertainty and support repeat business.

4. Treat repair and refurbishment as connected markets

A business that supplies repair shops can also support refurbishers. Both need dependable displays, batteries, charging components, cameras, housing components and test equipment.

5. Invest in technical capability

As smartphones become more integrated, repair businesses can differentiate through board-level repair, microsoldering, diagnostics, data recovery, calibration and other specialized services where appropriate.

6. Use regulation as a planning signal

Parts availability, repair documentation and software access are becoming increasingly important in major markets. Suppliers should monitor regional requirements rather than treating right-to-repair as a single worldwide rule.

Smartphone aftermarket outlook for 2026–2030

The most important trend is not simply that more smartphones are being repaired. It is that the economics of keeping a device in use are changing.

New smartphone shipments are under pressure in 2026, while device prices and component costs are rising. At the same time, refurbishing markets continue to provide a lower-cost route to premium hardware, and repair regulations are improving access to parts and technical resources in some regions.

For the repair parts segment specifically, The Business Research Company projects growth from $23.45 billion in 2026 to $39.18 billion by 2030. This is a market-research forecast, not a guaranteed outcome, and it should not be confused with the value of the entire smartphone aftermarket.

The bigger opportunity

The strongest long-term opportunity is likely to sit at the intersection of repair, refurbishment, parts distribution and device longevity. Businesses that can provide reliable components, technical knowledge, testing and efficient fulfillment are better positioned than businesses competing only for the lowest part price.

Frequently asked questions

How big is the smartphone aftermarket in 2026?

There is no single authoritative 2026 figure that combines repair services, repair parts, refurbished phones, accessories and other aftermarket activities. Different research firms define the market differently. For example, The Business Research Company estimates the mobile device repair parts market at $23.45 billion in 2026, while Counterpoint separately tracks refurbished and pre-owned smartphone markets.

Is the smartphone repair parts market growing?

Yes. The Business Research Company estimates the mobile device repair parts market will grow from $20.67 billion in 2025 to $23.45 billion in 2026 and reach $39.18 billion by 2030.

Why are refurbished smartphones becoming more important?

Refurbished devices provide a lower-cost way to buy premium hardware. Counterpoint reported 5% global refurbished smartphone sales growth in 2024 and 3% growth in H1 2025, with stronger performance in several emerging markets.

Does right-to-repair increase access to smartphone parts?

In some jurisdictions, yes. The EU's smartphone ecodesign rules require certain critical spare parts to remain available for seven years after a model leaves the market and require professional repairers to receive them within 5–10 working days.

Which smartphone repair parts are most important?

Common categories include display assemblies, batteries, camera modules, charging components, connectors, buttons and speakers. Demand varies by device model, market and repair business, so supplier-level sales data is more useful than applying one global failure-rate estimate to every market.

If your iPhone battery no longer makes it through the day, replacing it is usually an easy decision. The harder part is choosing what to replace it with.

Alongside the standard-capacity OEM batteries, repair shops now offer high-capacity options that promise more usable time between charges. Some give a modest increase, while others are capacity much higher than the battery originally fitted to the phone.

At first glance, that sounds simple. In practice, capacity matters alongside cell quality, battery management, temperature control, charge reporting, and long-term stability. Let’s use the REPART iPhone 13 battery as an example, then look at why the capacity increase changes from one iPhone model to another.

What Does "High-Capacity" Really Mean?

The standard iPhone 13 battery is capacity at about 3,227mAh and 12.41Wh. The REPART iPhone 13 high-capacity battery is capacity at 3,450mAh, 3.84V, and 13.25Wh, with a 4.47V charge-limit voltage. That works out to roughly 7% more rated capacity.

Seven percent may not sound dramatic, but for someone who regularly finishes the day with little charge left, even a modest increase can be useful. The important point is that 7% is not a rule for every model.

For example, the iPhone 16 Pro has a standard-capacity figure of 3,582mAh, while a REPART high-capacity option is rated at 3,800mAh. That is an increase of about 6%. The iPhone 16 Pro Max shows a bigger spread. A standard-capacity battery is around 4,685mAh. REPART offers a 5,050mAh TI version and a 5,297mAh Select version, roughly 8% and 13% higher respectively.

Across the wider Select range, REPART lists some batteries with capacity increases of up to 39% compared with standard OEM-spec replacements. So when you see "high-capacity," don't assume a fixed percentage. Check the actual mAh figure for the model you're repairing.

Does More mAh Mean More Runtime?

Usually, the more genuine capacity gives the phone more energy to work with. But a 10% increase in mAh does not guarantee exactly 10% more screen time.

How long an iPhone lasts depends heavily on how it's used.

Watching video at moderate brightness is very different from recording 4K video, gaming, using GPS, or dealing with a poor cellular signal. Screen brightness, background apps, 5G, temperature, and processor load all change power use. That's why it's better to talk about rated capacity rather than promising a fixed number of extra hours.

A 3,450mAh iPhone 13 battery has more rated capacity than a 3,227mAh battery. Assuming both batteries are working properly, that gives the phone a larger energy reserve. The exact difference you notice from day to day will depend on how you use it. The standard iPhone 13 capacity of 3,227mAh and 12.41Wh is also documented by iFixit.

The Battery Chip Matters Too

Capacity gets most of the attention because it's easy to compare. The electronics attached to the cell are less visible, but they have an important job. The REPART iPhone 13 battery uses a TI chip solution with Impedance Track technology. REPART rates the system for 1% state-of-charge precision.

In plain language, the battery-management system is trying to answer one question accurately: how much usable charge is actually left? It's harder than it sounds.

Battery voltage changes with temperature, load, age, and state of charge. Poor fuel gauge can lead to the familiar "ghost percentage" problem, where a phone appears to have plenty of battery left and then drops quickly or shuts down sooner than expected.

TI's Impedance Track approach is designed to estimate remaining capacity using factors such as battery impedance, temperature, discharge behavior, and age.

It doesn't create extra capacity. It helps us track the capacity that's already there more accurately.

What Does Less Than 10µA Standby Consumption Mean?

REPART also specifies less than 10µA static consumption for the battery management board. This does not mean the whole iPhone uses less than 10µA overnight. The phone is still powered by wireless connections, background services, notifications, memory, and other hardware.

The figure refers only to battery-management electronics. Keeping that draw low reduces the energy the battery board uses while the phone is idle. It's a small part of overall battery life, but it shows that efficiency is being considered beyond simply increasing cell capacity.

Temperature Control Still Matters

Lithium-ion batteries don't like extreme heat or cold. Temperature affects charging, available power, and long-term battery health. The REPART iPhone 13 battery includes integrated IC thermal monitoring for real-time temperature control, including low-temperature charging conditions.

That matters because added capacity should not come at the expense of basic protection. A good high-capacity battery needs to balance energy density with stable charging and discharge behavior. A bigger mAh number isn't automatically better if the battery management system or cell quality is poor.

Does a High-Capacity Battery Wear Out Faster?

Not necessarily.

Battery aging is affected by heat, charge cycles, charging conditions, storage, cell chemistry, and manufacturing quality. Two batteries with the same capacity can age very differently. REPART describes its iPhone 13 battery as using a Pure Cobalt cell, intended to provide stable chemistry and slow capacity degradation.

That's useful to know, but specific lifespan promises still need long-term test data. For repair shops, the practical question isn't just how many mAh are printed on the label. It's whether the battery combines useful capacity with dependable fuel gauging, temperature monitoring, low board consumption, and consistent cell quality.

So, Is a High-Capacity iPhone Battery Worth It?

If the phone already needs battery replacement, a high-capacity option can be a sensible upgrade. For the iPhone 13, the jump from 3,227mAh to 3,450mAh is about 7%. On other models, the increase may be smaller or considerably larger.

The iPhone 16 Pro Max, for example, can move from around 4,685mAh to 5,050mAh or 5,297mAh depending on the REPART battery series. For a light user, the difference may be modest. For someone spending the day on calls, navigation, video, social apps, or mobile work, extra stored energy can be useful.

The same applies to repair shops.

A standard-capacity battery remains the straightforward replacement, while a high-capacity version gives customers an upgrade option when longer runtime matters to them.

It also gives technicians a clearer way to offer different levels of replacement instead of treating every battery as essentially the same product.

Don't Choose a Battery by Capacity Alone

This is probably the most important point. A battery with the biggest mAh number isn't automatically the best battery. If the cell quality is poor, the fuel gauge is inaccurate, or the battery-management board draws too much power or doesn't handle temperature properly, the extra capacity won't mean much. That's why the specifications behind the numbers matter.

With the REPART iPhone 13 battery, the 3,450mAh capacity is only one part of the story. The TI chip solution, Impedance Track fuel gauging, low static board consumption, thermal monitoring, and Pure Cobalt cells are there to support how the battery operates in everyday use.

For a repair shop or refurbisher, those details can matter just as much as the capacity increase itself.

The Bottom Line

High-capacity iPhone batteries can provide longer use between charges, but the improvement isn't the same for every model. The best way to judge one is to look past the words "high-capacity." Check the actual mAh increase, cell quality, battery-management system, temperature monitoring, and how accurately the battery reports its remaining charge.

For REPART's iPhone 13 battery, the 3,450mAh rating provides roughly 7% more nominal capacity than the standard 3,227mAh figure. Other models can offer different gains, and some batteries in REPART's wider high-capacity range are rated considerably higher than standard-capacity replacements. So rather than thinking of a high-capacity battery as a miracle upgrade, think of it as something more practical: more stored energy, with the electronics and cell design needed to manage that energy properly.