diff --git a/update.php b/update.php
new file mode 100644
index 0000000..76acd60
--- /dev/null
+++ b/update.php
@@ -0,0 +1,92 @@
+<?php
+
+// Fetch the current 3.x version from the downloads site API
+$ch = curl_init();
+
+curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
+curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
+curl_setopt($ch, CURLOPT_URL, 'https://downloads.joomla.org/api/v1/latest/cms');
+
+$result = curl_exec($ch);
+
+curl_close($ch);
+
+if ($result === false)
+{
+	echo 'Could not fetch version data, please check your connection.' . PHP_EOL;
+
+	exit(1);
+}
+
+$data = json_decode($result, true);
+
+foreach ($data['branches'] as $branch)
+{
+	if ($branch['branch'] === 'Joomla! 3')
+	{
+		$version = $branch['version'];
+	}
+}
+
+if (!isset($version))
+{
+	echo 'Joomla! 3.x version data not included in API response.' . PHP_EOL;
+
+	exit(1);
+}
+
+$urlVersion = str_replace('.', '-', $version);
+
+$filename = "Joomla_$version-Stable-Full_Package.zip";
+
+// Fetch the SHA1 signature for the file
+$ch = curl_init();
+
+curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
+curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
+curl_setopt($ch, CURLOPT_URL, "https://downloads.joomla.org/api//v1/signatures/cms/$urlVersion");
+
+$result = curl_exec($ch);
+
+curl_close($ch);
+
+if ($result === false)
+{
+	echo 'Could not fetch signature data, please check your connection.' . PHP_EOL;
+
+	exit(1);
+}
+
+$data = json_decode($result, true);
+
+foreach ($data['files'] as $file)
+{
+	if ($file['filename'] === $filename)
+	{
+		$signature = $file['sha1'];
+	}
+}
+
+if (!isset($signature))
+{
+	echo 'ZIP file SHA1 signature not included in API response.' . PHP_EOL;
+
+	exit(1);
+}
+
+foreach (['apache', 'apache-php7', 'fpm', 'fpm-php7'] as $variant)
+{
+	$dockerfile = __DIR__ . "/$variant/Dockerfile";
+
+	$fileContents = file_get_contents($dockerfile);
+	$fileContents = preg_replace('#ENV JOOMLA_VERSION [^ ]*\n#', "ENV JOOMLA_VERSION $version\n", $fileContents);
+	$fileContents = preg_replace('#ENV JOOMLA_SHA1 [^ ]*\n#', "ENV JOOMLA_SHA1 $signature\n\n", $fileContents);
+
+	file_put_contents($dockerfile, $fileContents);
+
+	// To make management easier, we use these files for all variants
+	copy(__DIR__ . '/docker-entrypoint.sh', __DIR__ . "/$variant/docker-entrypoint.sh");
+	copy(__DIR__ . '/makedb.php', __DIR__ . "/$variant/makedb.php");
+}
+
+echo 'Dockerfile variants updated' . PHP_EOL;
diff --git a/update.sh b/update.sh
deleted file mode 100755
index 1900b02..0000000
--- a/update.sh
+++ /dev/null
@@ -1,26 +0,0 @@
-#!/bin/bash
-set -e
-
-# TODO - We (Joomla) need to expose an alternate API to checking the latest version other than our XML files
-current="$(curl -A 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/44.0.2403.89 Safari/537.36' -sSL 'https://developer.joomla.org/latest_version.json' | sed -r 's/^.*"current":"([^"]+)".*$/\1/')"
-
-# We're putting a lot of trust in this process, once Joomla has an exposed API to query the SHA1 use that instead
-wget -O joomla.zip https://github.com/joomla/joomla-cms/releases/download/$current/Joomla_$current-Stable-Full_Package.zip
-sha1="$(sha1sum joomla.zip | sed -r 's/ .*//')"
-
-for variant in apache apache-php7 fpm fpm-php7; do
-	(
-		set -x
-
-		sed -ri '
-			s/^(ENV JOOMLA_VERSION) .*/\1 '"$current"'/;
-			s/^(ENV JOOMLA_SHA1) .*/\1 '"$sha1"'/;
-		' "$variant/Dockerfile"
-
-        # To make management easier, we use these files for all variants
-		cp docker-entrypoint.sh "$variant/docker-entrypoint.sh"
-		cp makedb.php "$variant/makedb.php"
-	)
-done
-
-rm joomla.zip