is it ok to use back NIS 2011?

with the NIS 2012 being so buggy, i think of switching back to NIS 2011.

 

is it safe to use back NIS 2011? any bugs or major problems with NIS 2011?

 

since NIS 2011 is no longer supported, will it pose any security risk to the users?

 

 

 

 

a side question when is NIS 2013 coming out?