[PHP] libphp5.so rebuild required?

[SAILESH KRISHNAMURTI, BLOOMBERG/ 731 LEXIN]

Hi, We are looking to upgrade php 5.2.1 to 5.2.8. Do we need to rebuild the 
libphp5.so also to detect the new version of underlying php or will the same 
old version of libphp5.so build for php 5.2.1, automatically detect a new 
underlying php installation? thanks