# 工程文库 vs 中天控股

The clearest difference is in-app purchases: 中天控股 at none against 工程文库's 4. 中天控股 also leads on ads (none vs shown) and update cadence (monthly vs every 4 months). On price and device support there is nothing between them.

Both are free to download. 工程文库 sells 4 one-off in-app purchases. 中天控股 asks for nothing beyond the download.

工程文库 ships an update every 4 months, 中天控股 monthly. The most recent releases landed on September 17, 2026 and September 10, 2026 respectively.

## The numbers

| Metric | 工程文库 | 中天控股 |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Every 4 months | **Monthly** |
| Size | 75 MB | 59 MB |
| Requires iOS | 14.0 | **12.0** |
| Devices | iPhone, iPod | iPhone, iPod |
| Age rating | 17+ | 4+ |
| Developer | [Changsha Henggong Technology Co., Ltd.](https://appshunter.io/developer/1696907784) | [杭州智晗信息技术有限公司](https://appshunter.io/developer/1255811002) |

## What reviewers say

### 工程文库

[App page](https://appshunter.io/ios/app/id6451134184)

**Features:** macOS Compatibility

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 工程文库 | $3.99 | one-time |
| 工程文库 | $7.99 | one-time |
| 工程文库 | $19.99 | one-time |
| 工程文库 | $39.99 | one-time |


### 中天控股

[App page](https://appshunter.io/ios/app/id6470347329)

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

**In-app purchases:** none


## Frequently asked questions

### Is 工程文库 free?

工程文库 is free to download, with in-app purchases available.

### Is 中天控股 free?

中天控股 is free to download, with no in-app purchases.

### Do 工程文库 or 中天控股 have ads?

工程文库 shows ads; 中天控股 does not.

### Which is updated more often, 工程文库 or 中天控股?

工程文库 ships an update every 4 months, and 中天控股 monthly. Most recently, 工程文库 was updated on September 17, 2026 and 中天控股 on September 10, 2026.

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