Release note of the version are here
In the event generation menu an option to prepare old-format event files (a-la 4.2 and before) has been added.
How to install on 64bit lxplus.cern.ch machines, where 32bit libisajet and libmath from cernlib are found by ./configure in the directory /cern/pro/lib:
(0) make clean
(1) change in CFLAGS: -Wall -DNUM_LONG -DCOMPHEP -m32 (instead of -Wall -DNUM_LONG -DCOMPHEP )
(2) change in CLIBS: -L/usr/X11R6/lib ( instead of -L/usr/X11R6/lib64 )
then compile by 'make'