# # Simple Invoice vs Shift Safe

The clearest difference is in-app purchases: Shift Safe at none against # Simple Invoice's 2. Shift Safe also leads on iOS requirement (13.0 vs 15.6). # Simple Invoice's advantage is update cadence (every 8 days vs every 4 months). On price, ads and device support there is nothing between them.

Both are free to download. # Simple Invoice sells 2 in-app purchases, starting at $1.99 per month. Shift Safe asks for nothing beyond the download.

# Simple Invoice ships an update every 8 days, Shift Safe every 4 months. Both last shipped on October 31, 2026.

## The numbers

| Metric | # Simple Invoice | Shift Safe |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 8 days** | Every 4 months |
| Size | 48 MB | 4 MB |
| Requires iOS | 15.6 | **13.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 12+ |
| Developer | [YUKI TANAIKE](https://appshunter.io/developer/478558546) | [Shift Safe Technologies Inc](https://appshunter.io/developer/1896736691) |

## What reviewers say

### # Simple Invoice

[App page](https://appshunter.io/ios/app/simple-invoice/id6761528129)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Invoice Pro (Monthly) | $1.99 | per month |
| Invoice Pro (Annual) | $18.00 | per year |


### Shift Safe

[App page](https://appshunter.io/ios/app/shift-safe/id6770357163)

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

**In-app purchases:** none


## Frequently asked questions

### Is # Simple Invoice free?

# Simple Invoice is free to download, with in-app purchases available.

### Is Shift Safe free?

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

### Do # Simple Invoice or Shift Safe have ads?

Neither # Simple Invoice nor Shift Safe shows ads.

### Which is updated more often, # Simple Invoice or Shift Safe?

# Simple Invoice ships an update every 8 days, and Shift Safe every 4 months. Most recently, # Simple Invoice was updated on October 31, 2026 and Shift Safe 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.*