# OTPL Solar vs FourStage

The clearest difference is update cadence: OTPL Solar at every 3 weeks against FourStage's every 4 months. 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.

OTPL Solar ships an update every 3 weeks, FourStage every 4 months. The most recent releases landed on September 19, 2026 and September 18, 2026 respectively.

## The numbers

| Metric | OTPL Solar | FourStage |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 weeks** | Every 4 months |
| Size | 58 MB | 149 MB |
| Requires iOS | 13.0 | 13.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 17+ |
| Developer | [AHASOLAR TECHNOLOGIES LIMITED](https://appshunter.io/developer/1632224285) | [Vertical Axion, LLC](https://appshunter.io/developer/1697138155) |

## What reviewers say

### OTPL Solar

[App page](https://appshunter.io/ios/app/otpl-solar/id1489169580)

**In-app purchases:** none


### FourStage

[App page](https://appshunter.io/ios/app/fourstage/id6451203518)

**Features:** macOS Compatibility, Apple Wallet

**In-app purchases:** none


## Frequently asked questions

### Is OTPL Solar free?

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

### Is FourStage free?

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

### Do OTPL Solar or FourStage have ads?

Neither OTPL Solar nor FourStage shows ads.

### Which is updated more often, OTPL Solar or FourStage?

OTPL Solar ships an update every 3 weeks, and FourStage every 4 months. Most recently, OTPL Solar was updated on September 19, 2026 and FourStage on September 18, 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.*