> ## Documentation Index
> Fetch the complete documentation index at: https://docs.summerengine.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Compatibility & upstream

> Generated Summer Engine product-release and upstream compatibility facts from the pinned engine contract.

This reference is generated from the Summer Engine compatibility contract at
`SummerEngine/SummerEngine:compatibility/summer-engine.json`, commit `b44e47792819fb402a2984cd79c7023cc8aa57f8`. The checked-in input is verified against SHA-256
`741bd8237868a395cad89bfa1c5a70ef5ca2cfcc829674047cab1b9e180c054a`; docs builds do not fetch mutable remote data.

## Product identity

**Summer Engine** is the product. Creators make a **Summer game** in
**GDScript** and use the **Summer SDK** for platform capabilities.
The product release is platform-staggered and separate from the upstream technical base.

| Platform | Summer Engine release | Authoritative engine source                                          |
| -------- | --------------------: | -------------------------------------------------------------------- |
| macOS    |              `0.5.58` | `modules/1summer_engine/summer_version.h` → `SUMMER_VERSION_MACOS`   |
| Windows  |              `0.5.59` | `modules/1summer_engine/summer_version.h` → `SUMMER_VERSION_WINDOWS` |

## Upstream technical base

| Field                      | Value                 |
| -------------------------- | --------------------- |
| Current upstream base      | `4.6.1`               |
| Planned next upstream base | `4.7.1`               |
| Policy                     | `continuous-upstream` |
| Build evidence             | `version.py`          |
| Verified                   | `2026-07-30`          |

The upstream base is a compatibility and lineage fact, not the Summer Engine product version.
Summer follows upstream continuously; neither the current nor planned upstream number is a
permanent Summer identity.

## Runtime and project compatibility

* Runtime compatibility: Unmeasured; no version is claimed.
* Minimum project compatibility: Unmeasured; no version is claimed.
* Recommended project compatibility: Unmeasured; no version is claimed.

Unmeasured values are intentionally `null` in the source contract. Do not infer a minimum
from `project.godot`, copied prose, or an older setup guide.

## Where upstream terminology belongs

Godot references remain in migration, plugin and GDExtension compatibility, upstream
contribution, attribution, and legal contexts. Default creator onboarding installs and uses
Summer Engine.

<CardGroup cols={2}>
  <Card title="Previous: Naming" icon="arrow-left" href="/api-reference/summer-sdk/naming">
    Review creator-facing names and stable wire identifiers.
  </Card>

  <Card title="Next: Existing-project migration" icon="arrow-right" href="/migration/godot">
    Bring an existing Godot project into Summer Engine.
  </Card>
</CardGroup>