iPhone Duo compatibility report: 3.6% adapted, 96% never checked

As of October 24, 2026, Duo Tracker lists 4,672 apps across 4,989 regional records. 181 records are verified as adapted, or 3.6%; 4,789 are not checked, or 96.0%.

That needs a caveat before anything else: 3.6% is not the adaptation rate of iPhone Duo — it is how complete this directory is. Here is the data, cut five ways.

1. At a glance

Status	Records	Share
Adapted	181	3.6%
Partially adapted	4	0.1%
In progress	15	0.3%
Not checked	4,789	96.0%
Total	4,989	100%

At the app level: of 4,672 apps, 317 are on sale in both storefronts; 172 have a result in at least one region (3.7%); deduplicated into “adapted or partially adapted”, 160 apps.

2. China and the US: 0.7 points apart

Region	Records	Adapted	Not checked	Adapted rate	Checked
China	2,441	96	2,334	4.1%	4.4%
United States	2,548	85	2,455	3.4%	3.7%

“Adapted rate” counts adapted plus partially adapted; “checked” adds in progress. Partial adds 3 records in China and 1 in the US, and in-progress 8 and 7. The two regions are less than a point apart, and both have a checked rate near 4% — today the gap between regions is mostly about whether anyone has tested the app, not about how the app behaves.

3. On the chart vs off it: 4.4×

Group	Records	Adapted	Not checked	Adapted rate
Currently charting	300	39	256	13.7%
Off the chart	4,689	142	4,533	3.1%

“Currently charting” means the top 200 free apps in China and the top 100 in the US, 300 records in total. Charting apps are 4.4 times more likely to have a result, but that is a matter of where checking effort goes: chart apps are more visible and attract more feedback, so they get tested first. Reading it as “charting apps are better adapted” overstates the gap.

4. Higher rank means better compatibility? No

Rank	China records	China rate	US records	US rate
1–10	10	10.0%	10	20.0%
11–25	15	20.0%	15	13.3%
26–50	25	32.0%	25	16.0%
51–100	50	26.0%	50	8.0%
101–200	100	4.0%	—	—

In China the best band is 26–50 (32%), while the top 10 has a single adapted app (10%). A plausible explanation: the Chinese top 10 are the largest super-apps, with long release and adaptation cycles, whereas ranks 26–100 are mostly utilities and content apps that ship quickly and have more reason to optimise for a larger canvas. The US top 10 sits at 20%, but on ten records that is not much to go on.

5. 25 categories, from 14.9% to zero

Category	Records	Adapted	Partial	Adapted rate
Productivity	228	34	0	14.9%
Photo & video	216	19	0	8.8%
Music	210	15	0	7.1%
Health & fitness	213	14	0	6.6%
Entertainment	210	13	0	6.2%
Social networking	202	9	2	5.4%
Travel	209	9	0	4.3%
Games	214	7	2	4.2%
Finance	207	8	0	3.9%
Lifestyle	216	7	0	3.2%
Business	205	6	0	2.9%
Food & drink	208	6	0	2.9%
Weather	203	5	0	2.5%
Shopping	201	5	0	2.5%
Sports	203	4	0	2.0%
Magazines	50	1	0	2.0%
Utilities	215	4	0	1.9%
Books	225	4	0	1.8%
Navigation	201	3	0	1.5%
Graphics & design	204	3	0	1.5%
Reference	208	3	0	1.4%
Education	205	2	0	1.0%
News	134	0	0	0%
Medical	200	0	0	0%
Developer tools	202	0	0	0%

The spread across categories is an order of magnitude wider than across regions. Productivity, photo, music and health happen to be the categories where a bigger screen genuinely adds something — an extra column of text, a larger preview, another row of tracks. News, medical and developer tools have no results yet, which says nothing about whether they work, only that they have not been reached.

“Partially adapted” appears only in social networking and games, four records in total, which matches the usual pattern: split views work, but some screens are still stretched.

6. Dual-storefront apps: 317, nearly 90% unchecked on both sides

Status pair	Apps	Share
Adapted in both	25	7.9%
Not checked in both	283	89.3%
Adapted in one, not checked in the other	5	1.6%
Partial in one, not checked in the other	1	0.3%
Adapted in one, in progress in the other	1	0.3%
In progress in both	2	0.6%
Total	317	100%

31 dual-storefront apps have been marked adapted at least once, and 25 of them are adapted in both regions — 80.6%. Compatibility looks like a property of the app rather than of the region: the same code on two storefronts usually behaves the same way unfolded. The regional difference comes from checking progress instead: seven apps have a result on one side only.

7. Where the recommended list sits

All 35 recommended apps are verified as adapted in China, and 14 of them are on sale in both storefronts. Against 160 apps with a result, the list is about a fifth. By category: photo & video 6, productivity 5, health & fitness 5, music 4 — the product of manual selection, not evidence that these categories are better overall, only that they more often yield apps that are genuinely nicer to use.

8. Compared with October 23

Metric	Oct 23	Oct 24	Change
Apps	4,670	4,672	+2
Regional records	4,985	4,989	+4
Adapted	175	181	+6
Partially adapted	4	4	0
In progress	15	15	0
Not checked	4,791	4,789	−2

Four records were added in a day, all of them adapted; two more moved from not checked to adapted. The pace says something: new conclusions arrive in single digits per day, and at that rate the remaining 4,789 records will take a long time.

9. What this data cannot tell you

• Not checked is not the same as not compatible. 96% simply has not been looked at.
• Checking is not random sampling. Of the 200 verified records, 181 are adapted (90.5%), 4 partial, 15 in progress and none not adapted. Those apps came from visitor feedback, recommendation candidates and the top of the charts, which skews towards apps that look like they will work. The 90.5% is not an overall adaptation rate.
• The fields are incomplete. Of 200 verified records, 47 carry a test date, 6 a tested version and none an iOS version. So “a new release triggers a recheck” still depends on a person noticing; version drift cannot be computed yet.

10. Conclusions

1. 3.6% is completeness, not compatibility. It is too early to state an overall adaptation level for iPhone Duo; the sample cannot support it.
2. The most useful reading right now is a whitelist. Of 160 apps with a result, 156 are adapted. To check your own app, start by seeing whether it is in that pool.
3. The top of the chart is not where compatibility is best. China’s top 10 has one adapted app; ranks 26–50 do best. The bigger the app, the longer the adaptation cycle.
4. Compatibility looks like an app property, not a regional one. Of 31 dual-storefront apps with a result, 25 agree across regions (80.6%).
5. Category differences dwarf regional ones. Productivity is at 14.9%; news, medical and developer tools are at zero. What differs is whether anyone has optimised for the larger screen, not which country an app comes from.
6. The next step is structure, not volume. Testing the top 50 in each region would produce the first 100 records with statistical meaning; filling in test dates and tested versions would make the “results are bound to a version” promise true for more than a handful of records.

11. How to look up your app

• Search by app name, developer, App ID or alias, with fuzzy matching;
• Filter by status: adapted, partially adapted, in progress, not adapted, not checked — each with its own definition;
• See only apps with a result on the app compatibility list, then narrow by category and status;
• Browse by category: Apple’s official categories, 25 of them present in the data today;
• Nothing found: the app is not listed or not checked yet — the feedback form in the footer is the way to tell us.

The method here is fixed, so it can be recomputed after every data refresh. Next time, the number worth watching is how fast “not checked” falls, not how fast “adapted” rises — the former is what coverage looks like.