# Delta Emulator for iOS: What rileytestut/Delta Actually Installs and What It Costs You

> Delta is an all-in-one classic console emulator for non-jailbroken iOS devices, distributed through AltStore rather than the App Store. Its modular core design and seven-day refresh requirement shape who should adopt it.

**rileytestut/Delta** — Delta is an all-in-one classic video game emulator for non-jailbroken iOS devices.

- Repository: https://github.com/rileytestut/Delta
- Stars: 6,133 · Forks: 480
- Language: Swift
- License: AGPL-3.0
- Published: 2026-09-22 · Updated: 2026-09-22 · Language: en
- Canonical page: https://hysenlabs.com/projects/rileytestut-delta

## The problem Delta solves on iOS, and who it is for

iOS has no general-purpose emulator category in the App Store, and most emulation projects for Apple devices historically assumed a jailbreak. Delta targets the gap between those two facts. The README describes it as "an all-in-one classic video game emulator for non-jailbroken iOS devices," which is the whole pitch in one line. You keep a stock device, you install a single app, and you get Game Boy Advance, Nintendo 64, Nintendo DS and four other systems in one interface instead of juggling separate emulators.

The project is the successor to GBA4iOS, which the author built in high school with Paul Thorsen. That history matters for expectations: Delta was rebuilt from scratch for modern iOS, and the supported list has grown from one handheld to NES, SNES, N64, Game Boy, Game Boy Color, GBA, DS and a beta Sega Genesis core. The audience is the person who already owns an iPhone or iPad, has a ROM collection, and wants a native-feeling front end rather than a desktop emulator ported badly to a touchscreen.

## Seven emulator cores behind one Swift app

Delta does not write its own CPU emulation. The README lists a mature upstream core per system: Nestopia for NES, Snes9x for SNES, mupen64plus for N64, Gambatte for Game Boy and Game Boy Color, visualboyadvance-m for GBA, melonDS for DS, and Genesis Plus GX for the beta Genesis support. That is a deliberate architectural bet. The project owns the iOS shell, the database, the save-state plumbing and the UI, and delegates accuracy to codebases that have been tested for years elsewhere.

Structurally, each core lives in its own GitHub repository and is added to the main project as a submodule. The repository layout reflects this: there are Cores/, Systems/, DeltaCore, DeltaFeatures/ and DeltaPreviews/ directories, plus a Podfile and Podfile.lock. The README also notes that Delta depends on two private frameworks, Roxas and Harmony, which the author uses to share code between his apps. That last detail is the sharpest edge for anyone hoping to build the project themselves: a public repository that links private frameworks is not fully buildable from source by an outsider, and the README does not document a workaround.

The app repo itself is described as a regular sandboxed iOS application containing storyboards, app-specific view controllers and database logic. The upside of the split is that a core can be updated without touching the app shell. The cost is a submodule tree that has to be kept in sync, which is a common source of build friction in projects of this shape.

## Installing Delta with AltStore, step by step

Delta is not on the App Store. The README explains why in plain terms: the project was developed assuming Apple would allow it, Apple changed its mind, and the author built AltStore as the distribution channel. AltStore is now described as the official way to install Delta.

The documented flow starts on a computer. Download AltServer for Mac or PC from altstore.io, connect the iOS device with a Lightning cable or USB-C for iPads, then follow the AltStore FAQ instructions to install AltStore onto the device.

```bash
# Download AltServer for macOS or Windows from https://altstore.io
# Connect the iOS device with a Lightning cable (or USB-C for iPads)
# Follow https://altstore.io/faq/ to install AltStore onto the device
```

Once AltStore is on the device, the README gives the remaining steps: open AltStore, go to the Browse tab, find Delta, and press the FREE button to begin installing.

```bash
# On the iOS device:
# 1. Open AltStore
# 2. Navigate to the "Browse" tab
# 3. Find Delta and press the FREE button
```

The refresh rule is the part people miss. The README states that after installing Delta with AltStore you need to refresh it at least once every 7 days to prevent it from expiring and requiring a reinstallation. AltStore attempts background refreshes when the device is on the same WiFi as AltServer, and you can also press "Refresh All" manually. AltStore also surfaces new releases so Delta can be updated from inside AltStore.

There is a second path. The README says you are welcome to download the compiled .ipa files from Releases and sideload them with whatever method you prefer, but you will not receive automatic updates and will have to re-sideload each new version by hand. That trade is worth stating plainly: the manual route removes the weekly AltStore refresh but replaces it with manual version tracking.

## Delta Sync, save states and the features that carry the app

The feature list is long, but a few items change how the app is used day to day. Delta Sync keeps games, game saves, save states, cheats, controller skins and controller mappings consistent across devices, backed by either Google Drive or Dropbox. It also keeps version histories, so a synced item can be restored to an earlier version. For anyone playing the same save on an iPhone and an iPad, this is the feature that makes the setup coherent rather than two separate libraries.

Save states are handled with more care than most emulators bother with. You can save and load from the pause menu, lock a save state so it cannot be overwritten by accident, and the app automatically makes backup save states. Quick Save and Quick Load actions exist but the README ties them to an external controller, so a touch-only user does not get the one-button shortcut.

Controller support covers PS4, PS5, Xbox One S, Xbox Series X and MFi pads, plus Bluetooth and wired keyboards and the Apple Smart Keyboard. Button mappings are configurable per system and per controller, and buttons can be mapped to Quick Save, Quick Load and Fast Forward. There is also a Hold Button feature that keeps a chosen button pressed for you, which is aimed at games with a constant run button. Cheat code support varies by system: Game Genie on NES, SNES and GBC, GameShark on N64 and GBC, Action Replay on SNES, GBA and DS, Code Breaker on GBA, and Pro Action Replay on SNES. The README lists gyroscope support as limited to WarioWare: Twisted! and microphone support as DS only, which is a useful reminder that these are per-core capabilities rather than app-wide ones.

## Where Delta is the wrong tool

The distribution model is the first limitation, and it is not a small one. A seven-day refresh cycle means Delta is a poor fit for a device that travels without a companion computer, or for a child's iPad where nobody is going to run AltServer reliably. The README is explicit that missing the refresh window causes the app to expire and require reinstallation. Anyone expecting an install-once appliance will be disappointed.

The second limitation is platform. This is an iOS application, and nothing in the README suggests any other target. If you want emulation on Android, Windows or a handheld, Delta is simply not the project for you, regardless of how good the cores are.

The third is buildability. The dependency on the private Roxas and Harmony frameworks means the public repository is not a complete recipe for producing your own binary, and the README does not describe how an outside contributor obtains them. The compiled .ipa route sidesteps this, but it also means trusting a prebuilt artifact rather than building it yourself.

Finally, the Genesis core is marked in beta in the README. Treat Sega Genesis support as provisional rather than equivalent to the other seven systems.

## How Delta differs from RetroArch and standalone emulators

The obvious alternative for multi-system emulation is RetroArch, which takes the opposite architectural approach. RetroArch is a front end built around libretro cores, and it runs across many platforms including desktop and Android. Delta is a single-platform iOS app with cores pulled in as Git submodules and compiled into the project. The practical difference: RetroArch gives you portability and a much larger configuration surface, while Delta gives you a native iOS interface, automatic box art, and a curated set of cores chosen by one maintainer.

Standalone emulators such as the upstream projects Delta depends on are the other comparison. melonDS and mupen64plus exist on their own, and a technically inclined user could run them on a desktop. Delta's contribution is the iOS packaging: touch controls, controller mapping, save-state management, sync and a database of artwork. If you are emulating on a laptop, Delta adds nothing. If you are emulating on an iPhone without a jailbreak, it is one of the few options with this breadth.

Licensing separates the projects too. Delta is AGPL-3.0, which is a strong copyleft licence. The README does not discuss the implications, and this is not legal advice, but anyone planning to fork Delta, ship a modified build, or run a modified version as a network service should read the AGPL-3.0 text in the COPYING file before assuming the terms are the same as a permissive licence.

## Maintenance, releases and upgrade cost

The repository is not archived, and the last push was on 2026-07-30. The release cadence visible in the project's releases is slower than the commit activity: v1.6 landed on 2024-07-11, v1.5 on 2024-02-01, and v1.4 on 2023-02-28. That gap between steady commits and infrequent tagged releases is normal for an app that ships through AltStore, where updates are pushed to users without a version tag for every change.

The upgrade path is mostly automatic if you installed through AltStore, since the README says AltStore notifies you of new updates and lets you update Delta from within it. If you sideloaded an .ipa manually, every upgrade is a manual re-sideload. That is the real ongoing cost of the project: not money, but a recurring operational task, either the weekly refresh or the manual version tracking.

On licensing, the AGPL-3.0 badge and the COPYING file at the repository root are the authoritative sources. The README does not spell out what redistribution requires, so treat the licence text itself as the reference rather than any summary.

## Conclusion

Adopt Delta if you want NES through DS emulation on a non-jailbroken iPhone or iPad and you accept a weekly refresh through AltStore. Do not adopt it if you need an App Store install, an Android build, or a set-and-forget setup, because the README states the app expires after seven days without a refresh. Before installing, verify that AltServer supports your desktop OS, that you can keep the device and computer on the same WiFi for background refreshes, and that you are comfortable with the AGPL-3.0 obligations if you plan to modify or redistribute the code.

## FAQ

### How do I use the Delta emulator on iOS?

Install AltStore on your device using AltServer on a Mac or PC, open AltStore, go to the Browse tab, find Delta and press FREE. Once installed, you refresh it at least once every 7 days to keep it from expiring.

### What systems does Delta support?

The README lists NES, SNES, Nintendo 64, Game Boy and Game Boy Color, Game Boy Advance, Nintendo DS, and Sega Genesis or Mega Drive, with the Genesis support marked as in beta.

### Does Delta require a jailbreak?

No. The README describes Delta as an all-in-one classic video game emulator for non-jailbroken iOS devices, and it is distributed through AltStore rather than the App Store.

### Which emulator cores does Delta use?

Nestopia for NES, Snes9x for SNES, mupen64plus for N64, Gambatte for Game Boy and Game Boy Color, visualboyadvance-m for GBA, melonDS for DS, and Genesis Plus GX for the beta Genesis support.

### What licence is Delta released under?

Delta is licensed under AGPL-3.0, with the licence text in the COPYING file at the repository root. The README does not describe the redistribution obligations in detail.

## Sources

- [Issues](https://github.com/rileytestut/Delta/issues)
- [License: AGPL-3.0](https://github.com/rileytestut/Delta/blob/main/LICENSE)
- [README](https://github.com/rileytestut/Delta/blob/main/README.md)
- [Releases](https://github.com/rileytestut/Delta/releases)
- [rileytestut/Delta on GitHub](https://github.com/rileytestut/Delta)

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Hysen Labs editorial analysis, written from the project's own repository and release notes. Cite the canonical page: https://hysenlabs.com/projects/rileytestut-delta