Error: failed to delete buffer and headers already sent

[HDValentin]

On my site https://www.vbachem.de/PubwichFork/ I get several error messages.
Perhaps the script is not compatible with never php versions. I've tried PHP 7.1, 7.2, 7.3. Now active is 7.4:

"Deprecated: Function get_magic_quotes_runtime() is deprecated in /home/www/vbachem.de/PubwichFork/app/vendor/pear-cache-lite/Cache/Lite.php on line 757

Notice: ob_end_clean(): failed to delete buffer. No buffer to delete in /home/www/vbachem.de/PubwichFork/app/core/Pubwich.php on line 180

Warning: Cannot modify header information - headers already sent by (output started at /home/www/vbachem.de/PubwichFork/app/vendor/pear-cache-lite/Cache/Lite.php:757) in /home/www/vbachem.de/PubwichFork/app/core/Pubwich.php on line 181

Warning: Cannot modify header information - headers already sent by (output started at /home/www/vbachem.de/PubwichFork/app/vendor/pear-cache-lite/Cache/Lite.php:757) in /home/www/vbachem.de/PubwichFork/app/core/Pubwich.php on line 182

Warning: Cannot modify header information - headers already sent by (output started at /home/www/vbachem.de/PubwichFork/app/vendor/pear-cache-lite/Cache/Lite.php:757) in /home/www/vbachem.de/PubwichFork/app/core/Pubwich.php on line 183"

"Warning: Cannot modify header information - headers already sent by (output started at /home/www/vbachem.de/PubwichFork/app/vendor/pear-cache-lite/Cache/Lite.php:757) in /home/www/vbachem.de/PubwichFork/app/core/Pubwich.php on line 188

Deprecated: Function get_magic_quotes_runtime() is deprecated in /home/www/vbachem.de/PubwichFork/app/vendor/pear-cache-lite/Cache/Lite.php on line 757

Deprecated: implode(): Passing glue string after array is deprecated. Swap the parameters in /home/www/vbachem.de/PubwichFork/app/vendor/simplepie/library/SimplePie/Parse/Date.php on line 544

Deprecated: implode(): Passing glue string after array is deprecated. Swap the parameters in /home/www/vbachem.de/PubwichFork/app/vendor/simplepie/library/SimplePie/Parse/Date.php on line 545

Deprecated: Function get_magic_quotes_runtime() is deprecated in /home/www/vbachem.de/PubwichFork/app/vendor/pear-cache-lite/Cache/Lite.php on line 757

Deprecated: Function get_magic_quotes_runtime() is deprecated in /home/www/vbachem.de/PubwichFork/app/vendor/pear-cache-lite/Cache/Lite.php on line 757"

[haschek]

@HDValentin It did not work with PHP 7 at all or it just stopped working after upgrading to PHP 7.4?

[HDValentin]

@haschek I am not sure when it stopped working.