[TYPO3-english] Typo3 upgrade problem

[Pero Matic]

Hi. I just did an upgrade from 3.8.1 ( -> 4.0 -> 4.1 -> 4.2.8). It seems all 
is fine in FE but in BE i have a problem with flex forms. The content of 
flex form is displayed in one line. Anybody have an idea why this happens? 
There is also one warning (Warning: xml_parser_set_option() 
[function.xml-parser-set-option]: Unsupported target encoding "iso-8859-2" 
in) but i think i know how to solve this. Thx.