# Echo IM vs 知己

The clearest difference is update cadence: 知己 at every 3 days against Echo IM's weekly. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Echo IM ships an update weekly, 知己 every 3 days. The most recent releases landed on November 5, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | Echo IM | 知己 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Weekly | **Every 3 days** |
| Size | 95 MB | 8 MB |
| Requires iOS | 26.2 | **26.0** |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | 4+ | 12+ |
| Developer | [Tadwill & Co., Limited](https://appshunter.io/developer/351931205) | [伟烈 熊](https://appshunter.io/developer/6792607821) |

## What reviewers say

### Echo IM

[App page](https://appshunter.io/ios/app/echo-im/id6757745646)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### 知己

[App page](https://appshunter.io/ios/app/ai/id6816163811)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Echo IM free?

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

### Is 知己 free?

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

### Do Echo IM or 知己 have ads?

Neither Echo IM nor 知己 shows ads.

### Which is updated more often, Echo IM or 知己?

Echo IM ships an update weekly, and 知己 every 3 days. Most recently, Echo IM was updated on November 5, 2026 and 知己 on October 31, 2026.

---

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