# O vs CatDays

The clearest difference is review sentiment: CatDays at 83% against O's 0%. O's advantage is in-app purchases (none vs 8) and iOS requirement (9.0 vs 17.5). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. CatDays sells 8 one-off in-app purchases. O asks for nothing beyond the download.

Both ship on a similar rhythm, roughly every 3 weeks. The most recent releases landed on October 19, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | O | CatDays |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[3.9 (7 ratings)](https://appshunter.io/ios/app/catdays-cat-countdown/id6773580078/reviews)** |
| Number of ratings | — | **7** |
| Positive reviews | 0.0% of reviews | **83.3% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 weeks | Every 3 weeks |
| Monetization | **Free** | Free with in-app purchases |
| Size | 5 MB | 38 MB |
| Requires iOS | **9.0** | 17.5 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Shenzhen LINGXI Technology Co., Ltd](https://appshunter.io/developer/957619029) | [Lychee Intelligence Co., Ltd.](https://appshunter.io/developer/1778934446) |

## What reviewers say

### O

[App page](https://appshunter.io/ios/app/o-1/id1592076425)

This app helps you manage your weight and physical data. It collects information from body fat scales and your smartphone to calculate and store various health metrics.

**Highlights:** Body data collection, Health data analysis, Health data storage, Calculates health indices, Integrates with body fat scales

**Features:** macOS Compatibility

**In-app purchases:** none


### CatDays

[App page](https://appshunter.io/ios/app/catdays-cat-countdown/id6773580078)

Track important dates with a customizable cat companion. Choose from various feline friends to count down to future events or count up days since past milestones. Receive gentle reminders and view your progress with home screen widgets.

**Highlights:** Countdown and count-up modes, Selectable cat companions, Customizable reminders, Home screen widgets, iCloud synchronization, Ad-free experience

**In-app purchases (8)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Leo | $2.99 | one-time |
| Luna | $2.99 | one-time |
| Tofu | $2.99 | one-time |
| Ash | $2.99 | one-time |
| Milo | $2.99 | one-time |
| Pumpkin | $2.99 | one-time |
| Leo & Luna Pack | $3.99 | one-time |
| Original Cats Pack | $4.99 | one-time |


## Frequently asked questions

### Is O free?

O is free to download, with no in-app purchases.

### Is CatDays free?

CatDays is free to download, with in-app purchases available.

### Do O or CatDays have ads?

Neither O nor CatDays shows ads.

### Which is updated more often, O or CatDays?

O ships an update every 3 weeks, and CatDays every 3 weeks. Most recently, O was updated on October 19, 2026 and CatDays on October 28, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*