diff --git a/src/ApplicationLinker.php b/src/ApplicationLinker.php
index f835ec3..1812196 100644
--- a/src/ApplicationLinker.php
+++ b/src/ApplicationLinker.php
@@ -9,6 +9,7 @@
 use DirectoryIterator;
 use RecursiveDirectoryIterator;
 use RecursiveIteratorIterator;
+use ReflectionMethod;
 
 class ApplicationLinker
 {
@@ -176,16 +177,30 @@ public function run(): void
                         continue;
                     }
                     $this->filesystem->ensureDirectoryExists($appWebDir . DIRECTORY_SEPARATOR . $relativePath);
-                    $pathProxyToAutoloader = $this->filesystem->findShortestPath(
-                        $appWebDir . DIRECTORY_SEPARATOR . $relativePathName,
-                        $vendorDir . DIRECTORY_SEPARATOR . 'autoload.php',
-                        preferRelative: true
-                    );
-                    $pathProxyToFile = $this->filesystem->findShortestPath(
-                        $appWebDir . DIRECTORY_SEPARATOR . $relativePathName,
-                        $appVendorDir . DIRECTORY_SEPARATOR . $relativePathName,
-                        preferRelative: true
-                    );
+                    $reflection = new ReflectionMethod($this->filesystem, 'findShortestPath');
+                    if ($reflection->getNumberOfParameters() >= 4) {
+                        $pathProxyToAutoloader = $this->filesystem->findShortestPath(
+                            $appWebDir . DIRECTORY_SEPARATOR . $relativePathName,
+                            $vendorDir . DIRECTORY_SEPARATOR . 'autoload.php',
+                            preferRelative: true
+                        );
+                        $pathProxyToFile = $this->filesystem->findShortestPath(
+                            $appWebDir . DIRECTORY_SEPARATOR . $relativePathName,
+                            $appVendorDir . DIRECTORY_SEPARATOR . $relativePathName,
+                            preferRelative: true
+                        );
+                    } else {
+                        // Older composer versions don't support preferRelative
+                        $pathProxyToAutoloader = $this->filesystem->findShortestPath(
+                            $appWebDir . DIRECTORY_SEPARATOR . $relativePathName,
+                            $vendorDir . DIRECTORY_SEPARATOR . 'autoload.php',
+                        );
+                        $pathProxyToFile = $this->filesystem->findShortestPath(
+                            $appWebDir . DIRECTORY_SEPARATOR . $relativePathName,
+                            $appVendorDir . DIRECTORY_SEPARATOR . $relativePathName,
+                        );                        
+                    }
+
 
                     $originalContent = file_get_contents($appVendorDir . DIRECTORY_SEPARATOR . $relativePathName);
                     if (str_contains((string) $originalContent, '<?php')) {
diff --git a/src/HordeLocalFileWriter.php b/src/HordeLocalFileWriter.php
index 64a38af..ee8c525 100644
--- a/src/HordeLocalFileWriter.php
+++ b/src/HordeLocalFileWriter.php
@@ -56,7 +56,7 @@ private function processApp(string $app): void
             $hordeBaseDir = $this->vendorHordeDir;
         }
         $hordeLocalFileContent = sprintf(
-            "<?php if (!defined('HORDE_BASE')) define('HORDE_BASE', '%s');\nif (!defined('HORDE_CONFIG_BASE')) define('HORDE_CONFIG_BASE', '%s');\n",
+            "<?php\nif (!defined('HORDE_BASE')) define('HORDE_BASE', '%s');\nif (!defined('HORDE_CONFIG_BASE')) define('HORDE_CONFIG_BASE', '%s');\n",
             $hordeBaseDir,
             $this->configDir
         );
@@ -65,6 +65,14 @@ private function processApp(string $app): void
             $hordeLocalFileContent .= $this->_legacyWorkaround($this->filesystem->normalizePath($this->vendorDir));
             $hordeLocalFileContent .= "require_once('" . $this->vendorDir . "/autoload.php');";
         }
+        $appNameUpper = strtoupper($name);
+        $hordeLocalFileContent .= sprintf(
+            "\nif (!defined('%s_TEMPLATES')) define('%s_TEMPLATES', '%s');\n",
+            $appNameUpper,
+            $appNameUpper,
+            $this->vendorDir . DIRECTORY_SEPARATOR . $vendor . DIRECTORY_SEPARATOR . $name . DIRECTORY_SEPARATOR . 'templates',
+        );
+
         $autoloadExtraFilePath = $this->baseDir . '/var/config/autoload-extra.php';
         if (file_exists($autoloadExtraFilePath)) {
             $hordeLocalFileContent .= "\nrequire_once('$autoloadExtraFilePath')\n";
diff --git a/src/RegistrySnippetFileWriter.php b/src/RegistrySnippetFileWriter.php
index 4a5d806..faa0c0b 100644
--- a/src/RegistrySnippetFileWriter.php
+++ b/src/RegistrySnippetFileWriter.php
@@ -84,10 +84,12 @@ public function run(): void
             ' * - var/config/horde/registry-sub.domain.org.php' . PHP_EOL .
             ' */' . PHP_EOL;
 
+            $appInVendorDir = $this->baseDir . DIRECTORY_SEPARATOR . 'vendor' . DIRECTORY_SEPARATOR . $appVendor . DIRECTORY_SEPARATOR . $appName . DIRECTORY_SEPARATOR;
             if ($app == 'horde/horde') {
                 $registryAppFilename = $this->configRegistryDir . '/01-location-' . $appName . '.php';
                 $registryAppSnippet .=
-                '$this->applications[\'horde\'][\'fileroot\'] = $app_fileroot;' . PHP_EOL .
+                '$this->applications[\'' . $appName . '\'][\'fileroot\'] = \'' . $appInVendorDir . '\';' . PHP_EOL .
+                '$this->applications[\'' . $appName . '\'][\'templates\'] = \'' . $appInVendorDir . 'templates' . DIRECTORY_SEPARATOR . '\';' . PHP_EOL .
                 '$this->applications[\'horde\'][\'webroot\'] = $app_webroot;' . PHP_EOL .
                 '$this->applications[\'horde\'][\'jsfs\'] = $deployment_fileroot . \'/js/horde/\';' . PHP_EOL .
                 '$this->applications[\'horde\'][\'jsuri\'] = $deployment_webroot . \'js/horde/\';' . PHP_EOL .
@@ -98,7 +100,6 @@ public function run(): void
             } else {
                 // A registry snippet should ensure the install dir is known
                 $registryAppFilename = $this->configRegistryDir . '/02-location-' . $appName . '.php';
-                $appInVendorDir = $this->baseDir . DIRECTORY_SEPARATOR . 'vendor' . DIRECTORY_SEPARATOR . $appVendor . DIRECTORY_SEPARATOR . $appName . DIRECTORY_SEPARATOR;
                 $registryAppSnippet .=
                 '$this->applications[\'' . $appName . '\'][\'fileroot\'] = \'' . $appInVendorDir . '\';' . PHP_EOL .
                 '$this->applications[\'' . $appName . '\'][\'templates\'] = \'' . $appInVendorDir . 'templates' . DIRECTORY_SEPARATOR . '\';' . PHP_EOL .