There is nothing dangerous with this .pup, the difference is that it has its lv2 patched to enable peek and poke syscalls, that's it, it will not explode your console. You WILL need to use it if you want to play your backups in the future.
Oh common, the things we did with the first PSgroove rls and then the peek/poke syscalls. Then came Hermes and PL3 they all at one point had peek/poke so this is no different then running a old Jailbreak hex on ur dongle...
Besides, just having peek/poke ability doesnt brick your console unless u start tinkering with it, cuz todays backupmanagers doesnt peek or poke anymore...
Simple, if you use some game manager (Open Manager, multiMAN, GAIA, ...) to play your games, do not update to this .pup or any other fw that is not the 3.41.
The 3.55 is "new" to jailbreak, you can't load backups with it, only homebrews which does not need specials syscalls that are only available with the use of some payload (like PL3 or Hermes).
i just used a patched update file to install this and reinstalled geohot's jb over it (originally just had geohot's jb). everything seems to work the same. can't wait for a back up manager to update...