Scala 3.4.3 announcement (#1682)

* Scala 3.4.3 announcement

Author: WojciechMazur

_downloads/2024-10-23-3.4.3.md

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+---
+title: Scala 3.4.3
+start: 23 August 2024
+layout: downloadpage
+release_version: 3.4.3
+release_date: "August 23, 2024"
+permalink: /download/3.4.3.html
+license: <a href="https://www.scala-lang.org/license/">Apache License, Version 2.0</a>
+api_docs: https://www.scala-lang.org/api/3.4.3/
+---

_posts/2024-08-23-release-notes-3.4.3.md

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+---
+category: announcement
+permalink: /news/3.4.3
+title: "Scala 3.4.3 is now available!"
+---
+Scala 3.4.3 is now available!
+
+The hotfix version 3.4.3 is recommended for library authors who cannot or do not want Scala 3.5 upgrade, but want to keep their forward and backward binary compatibility.
+
+We expect that only a few library authors will be affected, because:
+
+- most library authors are using the Scala 3.3 LTS series. Staying on LTS is our standard recommendation for library authors.
+- the issue is specific to match types that are exposed in APIs
+
+This release reverts changes introduced in Scala 3.4.2 that led to binary incompatibility of match types produced by the compiler. You can read about this issue in [Scala 3 repository](https://github.com/scala/scala3/issues/21258). The new behaviour would be restored in some next major version (probably 3.6) after being well described and probably introducing a warning for the users.
+
+We recommend authors of Scala 3 libraries that use match types in their APIs to set up [TASTy MiMA](https://github.com/scalacenter/tasty-mima) checks as the extension to classic bytecode-based MiMa binary compatibility assertions.
+
+For a full list of changes and contributor credits, please refer to the [release notes](https://github.com/scala/scala3/releases/tag/3.4.3).