Our hosting company changes the PHP version from 5.5 to 7.0 and the default_charset is to be UTF-8. I changed the settings in NOF 2015 /Tools->Options->Current S`ite to UTF-8 but in php scripts e.g. TabTop and Forms Handler, despite the reintroduction of specific signs of the Eastern European alphabet, strange erroneous characters are displayed.
How to solve this problem ?

I am asking for help and thank you for the tips.