( ! ) Deprecated: Return type of Joomla\CMS\Date\Date::format($format, $local = false, $translate = true) should either be compatible with DateTime::format(string $format): string, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in C:\Sources\hsskcom\libraries\src\Date\Date.php on line 281
Call Stack
#TimeMemoryFunctionLocation
10.0007362528{main}( )...\index.php:0
20.0013364448require_once( 'C:\Sources\hsskcom\includes\framework.php )...\index.php:40
30.0136772080JError::setErrorHandling( $level = 8, $mode = 'message', $options = ??? )...\framework.php:23
40.0136772080Joomla\CMS\Log\Log::add( $entry = 'JError::setErrorHandling() is deprecated.', $priority = 16, $category = 'deprecated', $date = ???, $context = ??? )...\error.php:371
50.0138772616Joomla\CMS\Log\LogEntry->__construct( $message = 'JError::setErrorHandling() is deprecated.', $priority = 16, $category = 'deprecated', $date = NULL, $context = [] )...\Log.php:163
60.0138774872JLoader::loadByPsr4( $class = 'Joomla\\CMS\\Date\\Date' )...\LogEntry.php:119
70.0140775352include_once( 'C:\Sources\hsskcom\libraries\src\Date\Date.php )...\loader.php:557

( ! ) Deprecated: Return type of Joomla\CMS\Date\Date::setTimezone($tz) should either be compatible with DateTime::setTimezone(DateTimeZone $timezone): DateTime, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in C:\Sources\hsskcom\libraries\src\Date\Date.php on line 398
Call Stack
#TimeMemoryFunctionLocation
10.0007362528{main}( )...\index.php:0
20.0013364448require_once( 'C:\Sources\hsskcom\includes\framework.php )...\index.php:40
30.0136772080JError::setErrorHandling( $level = 8, $mode = 'message', $options = ??? )...\framework.php:23
40.0136772080Joomla\CMS\Log\Log::add( $entry = 'JError::setErrorHandling() is deprecated.', $priority = 16, $category = 'deprecated', $date = ???, $context = ??? )...\error.php:371
50.0138772616Joomla\CMS\Log\LogEntry->__construct( $message = 'JError::setErrorHandling() is deprecated.', $priority = 16, $category = 'deprecated', $date = NULL, $context = [] )...\Log.php:163
60.0138774872JLoader::loadByPsr4( $class = 'Joomla\\CMS\\Date\\Date' )...\LogEntry.php:119
70.0140775352include_once( 'C:\Sources\hsskcom\libraries\src\Date\Date.php )...\loader.php:557
Error: Failed to start application: Failed to start the session because headers have already been sent by "C:\Sources\hsskcom\libraries\src\Date\Date.php" at line 37.