diff --git a/README.md b/README.md
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+++ b/README.md
@@ -2,7 +2,7 @@
 
 base64 is a common way to represent arbitrary binary data as ASCII. JavaScript has Uint8Arrays to work with binary data, but no built-in mechanism to encode that data as base64, nor to take base64'd data and produce a corresponding Uint8Arrays. This is a proposal to fix that. It also adds methods for converting between hex strings and Uint8Arrays.
 
-It is currently at stage 3 of [the TC39 process](https://tc39.es/process-document/): it is ready for implementations. See [this issue](https://github.com/tc39/proposal-arraybuffer-base64/issues/51) for current status.
+It is currently at stage 4 of [the TC39 process](https://tc39.es/process-document/): it is complete and ready to be included in the standard.
 
 Try it out on [the playground](https://tc39.github.io/proposal-arraybuffer-base64/).
 
diff --git a/playground/index-raw.html b/playground/index-raw.html
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 <h1>Proposed Support for Base64 in JavaScript</h1>
 
 <h2 id="introduction">Introduction</h2>
-<p>This page documents a stage 3 proposal for native base64 and hex encoding and decoding for binary data in JavaScript, and includes a <strong>non-production</strong> polyfill you can experiment with in the browser's console.</p>
+<p>This page documents a stage 4 proposal for native base64 and hex encoding and decoding for binary data in JavaScript, and includes a <strong>non-production</strong> polyfill you can experiment with in the browser's console.</p>
 <p>The proposal would provide methods for encoding and decoding Uint8Arrays as base64 and hex strings.</p>
 <p>Feedback on <a href="https://github.com/tc39/proposal-arraybuffer-base64">the proposal's repository</a> is appreciated.</p>
 <p>Specification text for the proposal is available <a href="https://tc39.es/proposal-arraybuffer-base64/spec/">here</a>.</p>
diff --git a/spec.html b/spec.html
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@@ -3,7 +3,7 @@
 <pre class="metadata">
 title: Uint8Array to/from base64
 status: proposal
-stage: 3
+stage: 4
 location: https://github.com/tc39/proposal-arraybuffer-base64
 copyright: false
 contributors: Kevin Gibbons