Fatal error: Uncaught Error: Undefined constant "Patchwork\Utf8\MB_OVERLOAD_STRING" in /volume1/web/prisma/vendor/patchwork/utf8/src/Patchwork/Utf8/Bootup.php on line 45

Error: Undefined constant "Patchwork\Utf8\MB_OVERLOAD_STRING" in /volume1/web/prisma/vendor/patchwork/utf8/src/Patchwork/Utf8/Bootup.php on line 45

Call Stack:
    1.3048     361800   1. {main}() /volume1/web/prisma/index.php:0
    1.5095     362648   2. include('/volume1/web/prisma/common.php') /volume1/web/prisma/index.php:23
    4.7082     700968   3. require('/volume1/web/prisma/includes/utf/utf_tools.php') /volume1/web/prisma/common.php:97
    4.8774     700968   4. Patchwork\Utf8\Bootup::initMbstring() /volume1/web/prisma/includes/utf/utf_tools.php:28