For this base64 encoded string "Q8Ju/Mbi4UDGBt2aqXhG7Q=="
PHP 5.5 and lower returns this: CÂnüÆâá@ÆÝš©xFí
PHP 5.6 and higher returns this: C�n����@�ݚ�xF�
It appears to be a difference in how the function handles character encoding, but I can't find any documentation on it. I recently upgraded to a server using the latest version of PHP and encountered this error with data being sent to me, that I am not encoding. So using PHP 7, I need to be able to to decrypt the strings I am receiving to get the same result as PHP 5.5 and earlier.