diff --git a/libraries/src/Application/AdministratorApplication.php b/libraries/src/Application/AdministratorApplication.php
index b12d3cc970da6..8b3994ffe42f8 100644
--- a/libraries/src/Application/AdministratorApplication.php
+++ b/libraries/src/Application/AdministratorApplication.php
@@ -231,7 +231,15 @@ public function getTemplate($params = false)
 		$db = Factory::getDbo();
 
 		$query = $db->getQuery(true)
-			->select($db->quoteName(['s.template', 's.params', 's.inheritable', 's.parent']))
+			/*
+			 * It is important to use the asterisk for THIS select query here.
+			 * It is needed due to the core update process.
+			 * Depending on the version before the update new database columns are used before they exist.
+			 * This causes the update to crash with SQL error.
+			 *
+			 * Can be reviewed for Joomla! 5.0
+			 */
+			->select('s.*')
 			->from($db->quoteName('#__template_styles', 's'))
 			->join(
 				'LEFT',
@@ -265,7 +273,18 @@ public function getTemplate($params = false)
 		$template = $db->loadObject();
 
 		$template->template = InputFilter::getInstance()->clean($template->template, 'cmd');
-		$template->params = new Registry($template->params);
+		$template->params   = new Registry($template->params);
+
+		// We have to check required properties which may not exist during the upgrade process
+		if (!property_exists($template, 'parent'))
+		{
+			$template->parent = '';
+		}
+
+		if (!property_exists($template, 'inheritable'))
+		{
+			$template->inheritable = 0;
+		}
 
 		// Fallback template
 		if (!file_exists(JPATH_THEMES . '/' . $template->template . '/index.php')
diff --git a/libraries/src/HTML/HTMLHelper.php b/libraries/src/HTML/HTMLHelper.php
index da5d10d5b8a64..800185490a9c2 100644
--- a/libraries/src/HTML/HTMLHelper.php
+++ b/libraries/src/HTML/HTMLHelper.php
@@ -440,7 +440,7 @@ protected static function includeRelativeFiles($folder, $file, $relative, $detec
 				$template   = $app->getTemplate(true);
 				$templaPath = JPATH_THEMES;
 
-				if ($template->inheritable || !empty($template->parent))
+				if (!empty($template->inheritable) || !empty($template->parent))
 				{
 					$client     = $app->isClient('administrator') === true ? 'administrator' : 'site';
 					$templaPath = JPATH_ROOT . "/media/templates/$client";
diff --git a/libraries/src/Helper/ModuleHelper.php b/libraries/src/Helper/ModuleHelper.php
index 579ad4257e5b7..a01136739ce7f 100644
--- a/libraries/src/Helper/ModuleHelper.php
+++ b/libraries/src/Helper/ModuleHelper.php
@@ -335,7 +335,12 @@ public static function getLayoutPath($module, $layout = 'default')
 
 		// Build the template and base path for the layout
 		$tPath = JPATH_THEMES . '/' . $template . '/html/' . $module . '/' . $layout . '.php';
-		$iPath = JPATH_THEMES . '/' . $templateObj->parent . '/html/' . $module . '/' . $layout . '.php';
+
+		if (!empty($templateObj->parent))
+		{
+			$iPath = JPATH_THEMES . '/' . $templateObj->parent . '/html/' . $module . '/' . $layout . '.php';
+		}
+
 		$bPath = JPATH_BASE . '/modules/' . $module . '/tmpl/' . $defaultLayout . '.php';
 		$dPath = JPATH_BASE . '/modules/' . $module . '/tmpl/default.php';