Deprecated: Joomla\Input\Input implements the Serializable interface, which is deprecated. Implement __serialize() and __unserialize() instead (or in addition, if support for old PHP versions is necessary) in ...public_html/libraries/vendor/joomla/input/src/Input.php on line 41
Deprecated: Return type of Joomla\Input\Input::count() should either be compatible with Countable::count(): int, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in ...public_html/libraries/vendor/joomla/input/src/Input.php on line 170
Deprecated: Joomla\CMS\Input\Input implements the Serializable interface, which is deprecated. Implement __serialize() and __unserialize() instead (or in addition, if support for old PHP versions is necessary) in ...public_html/libraries/src/Input/Input.php on line 31
Warning: session_name(): Session name cannot be changed after headers have already been sent in ...public_html/libraries/joomla/session/handler/native.php on line 128
Deprecated: Joomla\CMS\Input\Cookie implements the Serializable interface, which is deprecated. Implement __serialize() and __unserialize() instead (or in addition, if support for old PHP versions is necessary) in ...public_html/libraries/src/Input/Cookie.php on line 21
Warning: session_cache_limiter(): Session cache limiter cannot be changed after headers have already been sent in /home/denvygxk/public_html/libraries/joomla/session/handler/native.php on line 235
Error: Failed to start application: Failed to start the session because headers have already been sent by "...public_html/libraries/vendor/joomla/input/src/Input.php" at line 41.
I want to upgrade the Joomla 3x install to Joomla 4x but I don' think I can easily. Is there a way to troubleshoot what might be stopping my Joomla 3x website from running on PHP 8.1?