updated letro README

README.md

@@ -1,52 +1,98 @@
-# Matrix Authentication Service (Letro Fork)
+# Letro Authentication Service
 
-> **This is a fork of [element-hq/matrix-authentication-service](https://github.com/element-hq/matrix-authentication-service)**  
-> Maintained by [Letro Tech GmbH](https://letro.com)
+This repository contains Letro's fork of the
+[Matrix Authentication Service (MAS)](https://github.com/element-hq/matrix-authentication-service),
+the OIDC-based authentication service for Matrix homeservers,
+developed by [Element](https://element.io/) (Element Creations Ltd. /
+New Vector Ltd.).
 
-MAS (Matrix Authentication Service) is a user management and authentication service for [Matrix](https://matrix.org/) homeservers. This fork contains modifications and customizations specific to Letro's deployment needs.
+It is published as the corresponding source for the Letro-operated
+authentication service, in compliance with the GNU Affero General
+Public License, version 3 (AGPLv3) §13.
 
-For the official upstream documentation, see: [element-hq.github.io/matrix-authentication-service](https://element-hq.github.io/matrix-authentication-service/index.html)
+## Role in the Letro stack
 
-## 📋 About this Fork
+The Letro Authentication Service is the OIDC provider used by the
+Letro-operated Matrix homeserver for sign-in, sign-up, account
+management and session handling. It is deployed alongside the
+homeserver via the unmodified upstream
+[Element Server Suite (ESS) Helm chart](https://github.com/element-hq/ess-helm)
+and is exposed to end users of the Letro service. Because the
+service is reached by users over a network and Letro modifies it,
+AGPLv3 §13 applies: every user interacting with the running service
+must be offered access to the corresponding source — see
+"Corresponding source" below.
 
-This repository is a fork of the upstream Matrix Authentication Service with customizations for Letro's infrastructure. 
+## Relationship to upstream
 
-**Upstream Repository**: [element-hq/matrix-authentication-service](https://github.com/element-hq/matrix-authentication-service)
+- Upstream project: <https://github.com/element-hq/matrix-authentication-service>
+- Upstream baseline used by this fork: see
+  [`UPSTREAM_VERSION`](UPSTREAM_VERSION)
+- Letro modifications, with dates, serving as the AGPLv3 §5(a)
+  modification notice for the work as a whole: see
+  [`FORK_DIVERGENCE.md`](FORK_DIVERGENCE.md)
 
-## 💬 Community
+Upstream technical documentation — build instructions, configuration
+reference, operations notes — applies unchanged. See the upstream
+[README](https://github.com/element-hq/matrix-authentication-service#readme)
+and [docs](https://element-hq.github.io/matrix-authentication-service/).
 
-For general Matrix Authentication Service discussion, join [#matrix-auth:matrix.org](https://matrix.to/#/#matrix-auth:matrix.org)
+## Status
 
-## 🛠️ Installation
+This repository is the production source for the authentication
+service deployed by the Letro-operated homeserver. It is published
+primarily to satisfy AGPLv3 §13; it is not a generally supported
+open-source project and is not intended for third-party reuse.
 
-For installation and configuration, refer to:
-- **Upstream documentation**: [element-hq.github.io/matrix-authentication-service/setup](https://element-hq.github.io/matrix-authentication-service/setup/)
-- Letro-specific deployment documentation (if applicable)
+## Copyright
 
-## ⚖️ Copyright & License
+```
+Copyright (c) 2026 Letro Tech GmbH <legal@letro.com>  -- modifications
+```
 
-Copyright 2021-2024 The Matrix.org Foundation C.I.C.
+The upstream copyright lines (Element Creations Ltd., New Vector
+Ltd., and the other upstream contributors) are preserved verbatim
+in the source files and in [`LICENSE`](LICENSE), as required by
+AGPLv3. Letro does not claim authorship of upstream code; the parts
+modified by Letro are identified in
+[`FORK_DIVERGENCE.md`](FORK_DIVERGENCE.md).
 
-Copyright 2024, 2025 New Vector Ltd.
+## License
 
-Copyright 2025, 2026 Element Creations Ltd.
+This software is dual-licensed by Element Creations Ltd. ("Element"):
 
-This software is dual-licensed by Element Creations Ltd (Element). It can be used either:
+1. for free under the GNU Affero General Public License, version 3
+   or (at your option) any later version (AGPLv3); or
+2. under a paid Element Commercial License agreement between you and
+   Element.
 
-(1) for free under the terms of the GNU Affero General Public License (as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version); OR
+Letro distributes this fork under option (1), AGPLv3. The full
+licence texts are in [`LICENSE`](LICENSE) and
+[`LICENSE-COMMERCIAL`](LICENSE-COMMERCIAL). Letro's own modifications
+are likewise licensed under AGPLv3.
 
-### Original Work
-Copyright 2021-2024 The Matrix.org Foundation C.I.C.  
-Copyright 2024, 2025 New Vector Ltd.  
-Copyright 2025, 2026 Element Creations Ltd.
+## Third-party components
 
-### Modifications
-Copyright 2026 Letro Tech GmbH
+The authentication service depends on third-party libraries under
+their own licences. A consolidated attribution list, generated from
+the Cargo dependency graph, is published at
+[`THIRD_PARTY_LICENSES.md`](THIRD_PARTY_LICENSES.md).
 
-This software is based on the Matrix Authentication Service and is licensed under the GNU Affero General Public License version 3 (AGPL-3.0).
+## Trademarks
 
-This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
+"Matrix" is a trademark of The Matrix.org Foundation C.I.C.
 
-This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.
+"Element", "Matrix Authentication Service" and "MAS" are trademarks
+of Element Creations Ltd. / New Vector Ltd.
 
-You should have received a copy of the GNU Affero General Public License along with this program. If not, see <https://www.gnu.org/licenses/>
+Letro is **not** affiliated with, endorsed by, or sponsored by The
+Matrix.org Foundation or Element. References to the foregoing names
+in this repository's source, documentation, history and
+configuration are made solely to identify the upstream protocol and
+the upstream project from which Letro is derived, as permitted by
+nominative fair use.
+
+## Contact
+
+Legal / licensing questions: <legal@letro.com>
+Operating entity / imprint: see <https://www.letro.com/imprint>