# B vs iEMS

The clearest difference is update cadence: B at every 3 weeks against iEMS's every 4 months. iEMS's advantage is iOS requirement (13.0 vs 15.6). 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.

B ships an update every 3 weeks, iEMS every 4 months. The most recent releases landed on October 5, 2026 and October 20, 2026 respectively.

## The numbers

| Metric | B | iEMS |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 weeks** | Every 4 months |
| Size | 44 MB | 41 MB |
| Requires iOS | 15.6 | **13.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [BOE Energy Technology Co., Ltd.](https://appshunter.io/developer/1476777673) | [Shenzhen ZTE Software Co., Ltd.](https://appshunter.io/developer/1863573894) |

## What reviewers say

### B

[App page](https://appshunter.io/ios/app/b-isolar/id1476777674)

**Features:** macOS Compatibility

**In-app purchases:** none


### iEMS

[App page](https://appshunter.io/ios/app/iems/id6450133373)

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

**In-app purchases:** none


## Frequently asked questions

### Is B free?

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

### Is iEMS free?

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

### Do B or iEMS have ads?

Neither B nor iEMS shows ads.

### Which is updated more often, B or iEMS?

B ships an update every 3 weeks, and iEMS every 4 months. Most recently, B was updated on October 5, 2026 and iEMS on October 20, 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.*