Hi Joshua,

1. Not all templates are Joomla 4.4 ready. Make sure that you updated template to last version. Always check J4 support BEFORE Joomla upgrade, otherwise we may not be able to help on the forum.
2. Some times old plugin may cause that problem, not template itself.
3. Force Joomla to show more details about source of error

I've already tried to force errors to display. No luck. No error is still displayed.

Control Sample: Changed template to Cassopia and I could see errors with no issues.

I also installed latest template version (the update normally just runs then shows a blank joomla warning notification)

Check if installed by You template has a J4 version, if NOT it means that cannot be used on Joomla 4.4 yet. Quick eye confirmation yes/no.

https://www.joomshaper.com/joomla-templates

Each template has color tag with Jx version that support.

seems it doesn't have J4 version

so you have the anwser.

Recover site from backup (or hosting backup) and keep J3.10 for now.

Hello,

Template now has J4 version.

But I'm still getting error.

0 Cannot access protected property Joomla\CMS\Menu\MenuItem::$params

Call stack

Function Location

1 () JROOT/templates/shaper_travelia/html/mod_menu/default.php:39 2 require() JROOT/modules/mod_menu/mod_menu.php:30 3 include() JROOT/libraries/src/Dispatcher/ModuleDispatcher.php:52 4 Joomla\CMS\Dispatcher\ModuleDispatcher::Joomla\CMS\Dispatcher{closure}() JROOT/libraries/src/Dispatcher/ModuleDispatcher.php:55 5 Joomla\CMS\Dispatcher\ModuleDispatcher->dispatch() JROOT/libraries/src/Helper/ModuleHelper.php:281 6 Joomla\CMS\Helper\ModuleHelper::renderRawModule() JROOT/libraries/src/Helper/ModuleHelper.php:161 7 Joomla\CMS\Helper\ModuleHelper::renderModule() JROOT/libraries/src/Document/Renderer/Html/ModuleRenderer.php:99 8 Joomla\CMS\Document\Renderer\Html\ModuleRenderer->render() JROOT/libraries/src/Document/Renderer/Html/ModulesRenderer.php:50 9 Joomla\CMS\Document\Renderer\Html\ModulesRenderer->render() JROOT/libraries/src/Document/HtmlDocument.php:565 10 Joomla\CMS\Document\HtmlDocument->getBuffer() JROOT/libraries/src/Document/HtmlDocument.php:833 11 Joomla\CMS\Document\HtmlDocument->_renderTemplate() JROOT/libraries/src/Document/HtmlDocument.php:637 12 Joomla\CMS\Document\HtmlDocument->render() JROOT/libraries/src/Application/CMSApplication.php:1025 13 Joomla\CMS\Application\CMSApplication->render() JROOT/libraries/src/Application/SiteApplication.php:724 14 Joomla\CMS\Application\SiteApplication->render() JROOT/libraries/src/Application/CMSApplication.php:298 15 Joomla\CMS\Application\CMSApplication->execute() JROOT/includes/app.php:61 16 require_once() JROOT/index.php:32