diff --git a/.eslintignore b/.eslintignore
index 09e033074..956c7ea05 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -1389,6 +1389,7 @@ packages/tools/updateMarkdownDoc.js
 packages/tools/utils/discourse.js
 packages/tools/utils/loadSponsors.js
 packages/tools/utils/translation.js
+packages/tools/validateFilenames.js
 packages/tools/website/build.js
 packages/tools/website/buildTranslations.js
 packages/tools/website/processDocs.test.js
diff --git a/.gitignore b/.gitignore
index 04ab9f7f9..38f234baa 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1368,6 +1368,7 @@ packages/tools/updateMarkdownDoc.js
 packages/tools/utils/discourse.js
 packages/tools/utils/loadSponsors.js
 packages/tools/utils/translation.js
+packages/tools/validateFilenames.js
 packages/tools/website/build.js
 packages/tools/website/buildTranslations.js
 packages/tools/website/processDocs.test.js
diff --git a/lint-staged.config.js b/lint-staged.config.js
index 4b350298d..799e354dd 100644
--- a/lint-staged.config.js
+++ b/lint-staged.config.js
@@ -23,5 +23,6 @@ module.exports = {
 	'*.{js,jsx,ts,tsx,task2}': 'yarn spellcheck',
 	'*.{js,jsx,ts,tsx,task3}': 'yarn packageJsonLint',
 	'*.{js,jsx,ts,tsx,task4}': 'yarn linter-precommit',
-	'*.{md,mdx}': 'yarn spellcheck',
+	'*.{md,mdx,task5}': 'yarn spellcheck',
+	'*.{md,mdx,task6}': 'yarn validateFilenames',
 };
diff --git a/package.json b/package.json
index 714edc4f1..46ac51a4e 100644
--- a/package.json
+++ b/package.json
@@ -59,6 +59,7 @@
     "updateMarkdownDoc": "node ./packages/tools/updateMarkdownDoc",
     "updateNews": "node ./packages/tools/website/updateNews",
     "updatePluginTypes": "./packages/generator-joplin/updateTypes.sh",
+    "validateFilenames": "node ./packages/tools/validateFilenames.js",
     "watch": "yarn workspaces foreach --parallel --verbose --interlaced --jobs 999 run watch",
     "watchWebsite": "nodemon --delay 1 --watch Assets/WebsiteAssets --watch packages/tools/website --watch packages/tools/website/utils --watch packages/doc-builder/build --ext md,ts,js,mustache,css,tsx,gif,png,svg --exec \"node packages/tools/website/build.js && http-server --port 8077 ../joplin-website/docs -a localhost\""
   },
diff --git a/packages/tools/validateFilenames.ts b/packages/tools/validateFilenames.ts
new file mode 100644
index 000000000..8d37a5bd9
--- /dev/null
+++ b/packages/tools/validateFilenames.ts
@@ -0,0 +1,35 @@
+// This is used to validate the Markdown filenames. The updateNews script uses the filename as the
+// Discourse external_id, however that ID does not support certain characters, such as ".".
+
+import { getRootDir } from '@joplin/utils';
+import { fileExtension } from '@joplin/utils/path';
+import { readdir } from 'fs/promises';
+import { filename } from '@joplin/lib/path-utils';
+
+const supportedExtensions = ['md', 'mdx'];
+const allowedRegex = '^[a-zA-Z0-9_-]+$';
+
+const main = async () => {
+	const readmeDir = `${await getRootDir()}/readme`;
+
+	const filePaths = await readdir(readmeDir, { recursive: true });
+
+	for (const filePath of filePaths) {
+		try {
+			const ext = fileExtension(filePath);
+			if (!supportedExtensions.includes(ext.toLowerCase())) continue;
+			if (!supportedExtensions.includes(ext)) throw new Error(`Invalid extension case (Supported extensions: ${JSON.stringify(supportedExtensions)})`);
+			const name = filename(filePath);
+			if (!name.match(new RegExp(allowedRegex))) throw new Error(`File format not allowed (Allowed characters: ${allowedRegex})`);
+		} catch (error) {
+			console.info(`Invalid filename: "${filePath}":`, error.message);
+			process.exit(1);
+		}
+	}
+};
+
+main().catch((error) => {
+	console.error('Fatal error');
+	console.error(error);
+	process.exit(1);
+});