in reply to Solaris, Perl 5.8 and use 5.005

What hardware are you running on? Eventually its going to wear out and you are going to need to upgrade anyway. 2.6 is WAY deprecated. Anyways assuming you are not going to upgrade the OS you could check out Sun's Live Upgrade option where you can build an alternate boot sector while running, then mount that..install the new version of perl there - Boot from the sector during the outtage window and test your apps. If they blow up you can boot back from the old sector and blow away the other one. If this is a multi-domain system (E10K, 6800, F15K)you could also DR in a spare board and do your testing that way