Hi Anshu,
all characters which invalidate an xml will cause an issue in PI. Provided you are using a mapping/ FCC etc.
Some characters have a special meaning in XML.
If you place a character like "<" inside an XML element, it will generate an error because the parser interprets it as the start of a new element.
This will generate an XML error:
<message>salary < 1000</message>
To avoid this error, replace the "<" character with an entity reference:
<message>salary < 1000</message>
There are 5 pre-defined entity references in XML:
< < less than
> > greater than
& & ampersand
' ' apostrophe
" " quotation mark
Regards
Anupam