Newstrip is only needed if you have extra profile fields in your UBB. Otherwise, upgrading is painless, tho you may wanna upgrade to 5.47e before moving up to 6.1.0.2. I believe the 6.1 upgrade process looks for files not included in 5.39 installations (date.pl, a few others). Increase the maxmem field in ubb_library.pl to whatever number profile fields you have, then upload 5.47e files and re-set/re-build general settings.
You can also use this file to strip extra profile fields:
https://www.ubbdev.com/hacks/deletehacklines.txt Rename it to deletehacklines.pl, upload in ascii to your ubb cgi directory and set its permissions to 755.
Upgrading should be painless then.
