Update README.md

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Author: SableRaf

README.md

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 This repository contains the source code for the [Processing](https://processing.org/) project for people who want to help improve the code.
 
+## Announcing Processing 4.3.1 (release candidate)
+
+We’re excited to announce the release candidate for Processing 4.3.1! This update brings tooling improvements and a friendlier experience for contributors. To learn more, read the [Processing 4.3.1 announcement](https://github.com/processing/processing4-carbon-aug-19/wiki/Announcing-Processing-4.3.1-(release-candidate)).
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 ## Using Processing
 
 If you're interested in *using* Processing, head over to the [download page](https://processing.org/download), or read more about the project on the [Processing website](https://processing.org/). There are also several [tutorials](https://processing.org/tutorials) that provide a helpful introduction. They are complemented by hundreds of examples that are included with the software itself.