---
title: "Version Compatibility"
manual: "Microsoft Exchange 365 Mailer"
version: "main"
permalink: "https://docs.typo3.org/permalink/oliverkroener/ok-exchange365-mailer:compatibility@main"
source: "Compatibility.rst"
rendered: "2026-10-04T20:03:13+00:00"
---

# Version Compatibility {#compatibility}

This extension is maintained as **one release line per TYPO3 major**. Composer selects
the matching line automatically when you run
[`oliverkroener/ok-exchange365-mailer`](https://packagist.org/packages/oliverkroener/ok-exchange365-mailer) without a version constraint.

## Support matrix {#compatibility-matrix}

| TYPO3 | Extension | Branch | PHP | Graph SDK | Status |
| --- | --- | --- | --- | --- | --- |
| 14.x | 4.4.x | `main` | 8.2 – 8.5 | ^2 | Active |
| 13.4 LTS | 4.4.x | `main` | 8.2 – 8.5 | ^2 | Active |
| 12.4 LTS | 4.4.x | `main` | 8.1 – 8.4 | ^2 | Active |
| 11.5 ELTS | 3.2.x | `feature-typo3-11` | 7.4 – 8.3 | ^2 | Maintenance |
| 10.4 ELTS | 2.2.x | `feature-typo3-10` | 7.2 – 7.4 | none (Guzzle) | Maintenance |
| 9.5 | 1.1.x | `feature-typo3-9` | 7.2 – 7.4 | none (Guzzle) | Maintenance |

> [!NOTE]
> The 1.x line for TYPO3 9.5 predates Symfony Mailer — TYPO3 9.5 still used
> SwiftMailer — so its transport is a `Swift_Transport` rather than the
> architecture described in [Architecture](https://docs.typo3.org/permalink/oliverkroener/ok-exchange365-mailer:architecture@main). Like every other
> line, it is covered by the [test matrix](https://docs.typo3.org/permalink/oliverkroener/ok-exchange365-mailer:testing@main). The 1.x and 2.x lines
> call Microsoft Graph directly over HTTP instead of through the Graph SDK.

## Pinning a version {#pinning-a-version}

Composer resolves the correct line on its own. Pin explicitly only when you need to:

```bash
# TYPO3 12, 13 or 14
composer require oliverkroener/ok-exchange365-mailer:^4.4

# TYPO3 11
composer require oliverkroener/ok-exchange365-mailer:^3.2

# TYPO3 10
composer require oliverkroener/ok-exchange365-mailer:^2.2
```

If `composer require` reports that the package cannot be resolved, the
cause is almost always a TYPO3 major that the requested version does not cover —
check the table above rather than forcing the constraint.

## What differs between the lines {#what-differs-between-the-lines}

The 4.x line is the reference implementation. The older lines differ in ways that
matter if you read the source or report a bug:

-   **Configuration precedence.** From 2.2.0 / 3.2.0 onwards all lines overlay
    frontend TypoScript on top of the mail settings **per key**. Earlier 2.x and 3.x
    releases let a frontend TypoScript configuration *replace* the mail settings
    wholesale.
-   **Frontend TypoScript access.** The 4.x line reads the `frontend.typoscript`
    request attribute. The 2.x and 3.x lines read `$GLOBALS['TSFE']->tmpl->setup`,
    which is the correct API on TYPO3 10 and 11 but was removed in TYPO3 13.
-   **Credential blinding.** The 4.x line uses a PSR-14 event listener, the 3.x line
    a hook. The 2.x line does not blind credentials at all.
-   **Graph SDK.** The 2.x line uses `microsoft/microsoft-graph` v1
    (`Microsoft\Graph\Graph`); 3.x and 4.x use v2 (`GraphServiceClient`).

> [!NOTE]
> **See also**
>
> [Architecture](https://docs.typo3.org/permalink/oliverkroener/ok-exchange365-mailer:architecture@main) describes the 4.x implementation in detail.