Upgraded my copy of Movable Type blogging software today (I use » Movable Type Open Source) .. to » v4.12, released last month.
Despite using Movable Type since 2003 (beginning with v2.63), this is the first time I've upgraded.
Previous "upgrades" were actually new installations, such as MT v3.35 (in April 2007) and v4.1 (last January), while leaving the old installations of Ye Olde Rad Blog untouched.
Upgrades make me nervous, cuz there's always a chance something might go wrong, and cause me to LOSE all the entries. (MTOS currently hosts ~50 entries.)
Now, with the new VPS, upgrades are easier, cuz I can use the Linux command line, which lets me overwrite old files with a single command. Very powerful .. but dangerous .. if I make a mistake (such as a simple type-o).