diff --git a/packages/php-wasm/node/bin/rebuild-while-asyncify-functions-missing.mjs b/packages/php-wasm/node/bin/rebuild-while-asyncify-functions-missing.mjs
index 6b38092ecc..6153c3516b 100644
--- a/packages/php-wasm/node/bin/rebuild-while-asyncify-functions-missing.mjs
+++ b/packages/php-wasm/node/bin/rebuild-while-asyncify-functions-missing.mjs
@@ -50,7 +50,8 @@ function getHash() {
 	return createHash('sha1')
 		.update(
 			fs.readFileSync(
-				new URL('../../compile/Dockerfile', import.meta.url).pathname
+				new URL('../../compile/php/Dockerfile', import.meta.url)
+					.pathname
 			)
 		)
 		.digest('hex');
diff --git a/packages/php-wasm/node/public/php_8_0.js b/packages/php-wasm/node/public/php_8_0.js
index a4c9458bf9..08379712d4 100644
--- a/packages/php-wasm/node/public/php_8_0.js
+++ b/packages/php-wasm/node/public/php_8_0.js
@@ -5858,23 +5858,15 @@ function _js_module_onMessage(data, bufPtr) {
  }
  if (Module["onMessage"]) {
   const dataStr = UTF8ToString(data);
-  return Asyncify.handleSleep((wakeUp => {
-   Module["onMessage"](dataStr).then((response => {
-    const responseBytes = typeof response === "string" ? (new TextEncoder).encode(response) : response;
-    const responseSize = responseBytes.byteLength;
-    const responsePtr = _malloc(responseSize + 1);
-    HEAPU8.set(responseBytes, responsePtr);
-    HEAPU8[responsePtr + responseSize] = 0;
-    HEAPU8[bufPtr] = responsePtr;
-    HEAPU8[bufPtr + 1] = responsePtr >> 8;
-    HEAPU8[bufPtr + 2] = responsePtr >> 16;
-    HEAPU8[bufPtr + 3] = responsePtr >> 24;
-    wakeUp(responseSize);
-   })).catch((e => {
-    console.error(e);
-    wakeUp(0);
-   }));
-  }));
+     return Asyncify.handleSleep((wakeUp => {
+        // This works in the register_shutdown_function() test:
+        // wakeUp(0);
+        // This breaks the register_shutdown_function() test:
+        setTimeout(() => {
+             wakeUp(0);
+        });
+        return;
+     }));
  }
 }
 
@@ -6645,7 +6637,8 @@ function _wasm_setsockopt(socketd, level, optionName, optionValuePtr, optionLen)
  return 0;
 }
 
-function _wasm_shutdown(socketd, how) {
+    function _wasm_shutdown(socketd, how) {
+        console.log("_wasm_shutdown");
  return PHPWASM.shutdownSocket(socketd, how);
 }
 
@@ -6764,7 +6757,8 @@ var Asyncify = {
   runtimeKeepalivePop();
   return start();
  },
- handleSleep: function(startAsync) {
+    handleSleep: function (startAsync) {
+     console.log("Called handleSleep in Asyncify.state=", Asyncify.state)
   if (ABORT) return;
   if (Asyncify.state === Asyncify.State.Normal) {
    var reachedCallback = false;
diff --git a/packages/php-wasm/node/src/test/php-asyncify.spec.ts b/packages/php-wasm/node/src/test/php-asyncify.spec.ts
index 363a1538cf..d33b5e5d93 100644
--- a/packages/php-wasm/node/src/test/php-asyncify.spec.ts
+++ b/packages/php-wasm/node/src/test/php-asyncify.spec.ts
@@ -28,22 +28,23 @@ const js = phpVars({
 const phpVersions =
 	'PHP' in process.env ? [process.env['PHP']] : SupportedPHPVersions;
 
-describe.each(phpVersions)('PHP %s – asyncify', (phpVersion) => {
+describe.each(['8.0'])('PHP %s – asyncify', (phpVersion) => {
 	const topOfTheStack: Array<string> = [
 		// http:// stream handler
-		`file_get_contents(${js['httpUrl']});`,
+		// `file_get_contents(${js['httpUrl']});`,
 
-		`$fp = fopen(${js['httpUrl']}, "r");
-		 fread($fp, 1024);
-		 fclose($fp);`,
-		// `getimgsize(${js['httpUrl']});`,
+		// `$fp = fopen(${js['httpUrl']}, "r");
+		//  fread($fp, 1024);
+		//  fclose($fp);`,
+		// // `getimgsize(${js['httpUrl']});`,
 
-		// Network functions from https://www.php.net/manual/en/book.network.php
-		`$fp = fsockopen(${js['host']}, ${js['port']});
-		 fwrite($fp, "GET / HTTP/1.1\\r\\n\\r\\n");
-		 fread($fp, 10);
-		 fclose($fp);`,
-		`gethostbyname(${js['httpUrl']});`,
+		// // Network functions from https://www.php.net/manual/en/book.network.php
+		// `$fp = fsockopen(${js['host']}, ${js['port']});
+		//  fwrite($fp, "GET / HTTP/1.1\\r\\n\\r\\n");
+		//  fread($fp, 10);
+		//  fclose($fp);`,
+		// `gethostbyname(${js['httpUrl']});`,
+		`post_message_to_js('');`,
 
 		// @TODO:
 
@@ -56,7 +57,12 @@ describe.each(phpVersions)('PHP %s – asyncify', (phpVersion) => {
 	let php: NodePHP;
 	beforeEach(async () => {
 		php = await NodePHP.load(phpVersion as any);
-		php.setPhpIniEntry('allow_url_fopen', '1');
+		// php.setPhpIniEntry('allow_url_fopen', '1');
+		php.onMessage(async () => {
+			// Sleep 10ms
+			await new Promise((resolve) => setTimeout(resolve, 10));
+			return 'Response';
+		});
 	});
 
 	describe.each(topOfTheStack)('%s', (networkCall) => {
@@ -84,7 +90,7 @@ describe.each(phpVersions)('PHP %s – asyncify', (phpVersion) => {
 			test('array_map', () =>
 				assertNoCrash(`
 					function top() { ${networkCall} }
-					array_map(array('top'), 'top');
+					array_map('top', array('top'));
 				`));
 
 			// Network calls in sort() would be silly so let's skip those for now.
@@ -191,13 +197,75 @@ describe.each(phpVersions)('PHP %s – asyncify', (phpVersion) => {
 				unset($x['test']);            
 			`));
 		});
+		describe('Shutdown handlers', () => {
+			// This test case works and it outputs "Before, Response, After"
+			test('post_message_to_js', () =>
+				assertNoCrash(`
+				echo 'Before, ';
+				echo post_message_to_js('');
+				echo ', After';
+			`));
+			// This case does not work as it outputs just "Before, "
+			// It only works with gethostbyname()
+			test.only('register_shutdown_function', async () => {
+				await assertNoCrash(`
+					register_shutdown_function(function() {
+						echo "Before, ";
+						// If this call is asynchronous, the stdout stream gets corrupted
+						// some reason and the output is not appended to the file anymore.
+						echo post_message_to_js(''); 
+						echo ", After";
+						file_put_contents('/internal/additional_info', 'file_put_contents got executed!');
+					});
+				`);
+
+				// The output data is not appended to the stdout file:
+				console.log('stdout: ', php.readFileAsText('/internal/stdout'));
+				await new Promise((resolve) => setTimeout(resolve, 100));
+				console.log('stdout: ', php.readFileAsText('/internal/stdout'));
+
+				// However, the file_put_contents() function actually gets executed:
+				console.log(
+					'additional_info: ',
+					php.readFileAsText('/internal/additional_info')
+				);
+
+				// Something must be off with the wasm_sapi_request_shutdown() function
+			});
+			test('register_shutdown_function with args', () =>
+				assertNoCrash(`
+				register_shutdown_function(function($a) { echo ${networkCall}  }, 1);
+			`));
+			test('register_shutdown_function with static method', () =>
+				assertNoCrash(`
+				class Top {
+					static function my_method() { ${networkCall} }
+				}
+				register_shutdown_function(['Top', 'my_method']);
+			`));
+		});
+		describe('Generators', () => {
+			test('generator', () =>
+				assertNoCrash(`
+				function gen() {
+					yield ${networkCall};
+					return 1;
+				}
+				foreach (gen() as $val) {}
+			`));
+		});
 	});
 
 	async function assertNoCrash(code: string) {
 		try {
+			console.log('Running:', code);
 			const result = await php.run({
 				code: `<?php ${code}`,
+				throwOnError: true,
 			});
+			console.log('result:', result.text);
+			console.log('errors:', result.errors);
+			console.log(result.exitCode);
 			expect(result).toBeTruthy();
 			expect(result.text).toBe('');
 			expect(result.errors).toBeFalsy();
diff --git a/packages/php-wasm/universal/src/lib/base-php.ts b/packages/php-wasm/universal/src/lib/base-php.ts
index 2c5ea22bb8..89d09477a6 100644
--- a/packages/php-wasm/universal/src/lib/base-php.ts
+++ b/packages/php-wasm/universal/src/lib/base-php.ts
@@ -654,6 +654,9 @@ export abstract class BasePHP implements IsomorphicLocalPHP {
 		}
 
 		const { headers, httpStatusCode } = this.#getResponseHeaders();
+		console.log(
+			'Preparing the PHP response based on /internal/stdout and /internal/stderr...'
+		);
 		return new PHPResponse(
 			httpStatusCode,
 			headers,