diff --git a/scripts/e2e-test-versions.js b/scripts/e2e-test-versions.js
index b45f8e2b..598e9e46 100644
--- a/scripts/e2e-test-versions.js
+++ b/scripts/e2e-test-versions.js
@@ -2,11 +2,26 @@ const { readFileSync } = require('fs');
 
 const versions = JSON.parse(readFileSync('./test/e2e/versions.json', 'utf8'));
 
+// GitHub Actions limits a job matrix to 256 configurations. The e2e matrix
+// multiplies each Electron version by 3 operating systems and 4 shards (12),
+// so we can test at most floor(256 / 12) = 21 Electron versions.
+const MAX_VERSIONS = 21;
+
+// Always test the oldest supported version, then fill the remaining budget with
+// the newest versions.
+function selectVersions(count) {
+  if (versions.length <= count) {
+    return versions;
+  }
+  return [...new Set([versions[0], ...versions.slice(versions.length - (count - 1))])];
+}
+
 if (process.env.GITHUB_REF && process.env.GITHUB_REF.includes('release/')) {
-  // For release builds we test all versions
-  console.log(JSON.stringify(versions));
+  // For release builds we test the oldest supported version and as many of the
+  // newest versions as the matrix limit allows.
+  console.log(JSON.stringify(selectVersions(MAX_VERSIONS)));
 } else {
-  const versionCount = process.platform === 'darwin' ? -3 : -7;
   // Otherwise we test the oldest supported version and the last 3 or 7 versions depending on the platform
-  console.log(JSON.stringify([versions[0], ...versions.slice(versionCount)]));
+  const versionCount = process.platform === 'darwin' ? 3 : 7;
+  console.log(JSON.stringify(selectVersions(versionCount + 1)));
 }