# Learn Immune System vs Displacement Reaction

The clearest difference is price: Displacement Reaction at $1.99 against Learn Immune System's $2.99. On update cadence, ads, in-app purchases and device support there is nothing between them.

Learn Immune System costs $2.99 and Displacement Reaction $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Learn Immune System ships an update every 36 months, Displacement Reaction every 33 months. The most recent releases landed on October 15, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | Learn Immune System | Displacement Reaction |
| --- | --- | --- |
| Price | $2.99 | **$1.99** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 36 months | **Every 33 months** |
| Size | 16 MB | 150 MB |
| Requires iOS | 11.0 | 11.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 12+ | 4+ |
| Developer | [Nurten PIRLI](https://appshunter.io/developer/1495958705) | [VIRTUAL FILAMENTS PRIVATE LIMITED](https://appshunter.io/developer/1474217212) |

## What reviewers say

### Learn Immune System

[App page](https://appshunter.io/ios/app/learn-immune-system/id1502997625)

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

**In-app purchases:** none


### Displacement Reaction

[App page](https://appshunter.io/ios/app/displacement-reaction/id1544602964)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Learn Immune System free?

Learn Immune System costs $2.99, with no in-app purchases.

### Is Displacement Reaction free?

Displacement Reaction costs $1.99, with no in-app purchases.

### Do Learn Immune System or Displacement Reaction have ads?

Neither Learn Immune System nor Displacement Reaction shows ads.

### Which is updated more often, Learn Immune System or Displacement Reaction?

Learn Immune System ships an update every 36 months, and Displacement Reaction every 33 months. Most recently, Learn Immune System was updated on October 15, 2026 and Displacement Reaction on October 6, 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.*