Ok, I solved my issue.
Symptoms were like that:
– with PHP Version 5.3.28, 0 byte response
– with PHP Version 5.4.23, 143 bytes text response Cannot use output buffering in output buffering display handlers in Unknown on line 0
– error log: PHP Fatal error: Allowed memory size of 134217728 bytes exhausted
It seemed that a plugin enabled output buffering, but I cannot find which one. So, I replaced
ob_clean(); // download.php:88
with
ob_end_clean();
which cleans and turns off output buffering.
Issue solved… Hoping not to interfere with other plugins.
