# Backlog by Time Engine vs Approval Studio

The clearest difference is update cadence: Backlog by Time Engine at every 3 weeks against Approval Studio's every 10 months. Backlog by Time Engine also leads on iOS requirement (16.4 vs 18.4). 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.

Backlog by Time Engine ships an update every 3 weeks, Approval Studio every 10 months. The most recent releases landed on October 7, 2026 and October 18, 2026 respectively.

## The numbers

| Metric | Backlog by Time Engine | Approval Studio |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 weeks** | Every 10 months |
| Size | 3 MB | 3 MB |
| Requires iOS | **16.4** | 18.4 |
| Devices | iPhone | **iPhone, iPad** |
| Age rating | 4+ | 4+ |
| Developer | [100-8 Studio](https://appshunter.io/developer/1436780503) | [HiTech Service LLC](https://appshunter.io/developer/1124417233) |

## What reviewers say

### Backlog by Time Engine

[App page](https://appshunter.io/ios/app/backlog-by-time-engine/id6470202026)

**Features:** macOS Compatibility

**In-app purchases:** none


### Approval Studio

[App page](https://appshunter.io/ios/app/approval-studio/id6747336607)

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

**In-app purchases:** none


## Frequently asked questions

### Is Backlog by Time Engine free?

Backlog by Time Engine is free to download, with no in-app purchases.

### Is Approval Studio free?

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

### Do Backlog by Time Engine or Approval Studio have ads?

Neither Backlog by Time Engine nor Approval Studio shows ads.

### Which is updated more often, Backlog by Time Engine or Approval Studio?

Backlog by Time Engine ships an update every 3 weeks, and Approval Studio every 10 months. Most recently, Backlog by Time Engine was updated on October 7, 2026 and Approval Studio on October 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.*