They do an annual rehab every winter. Sometimes they fix/re-skin the animatronics during the month or so long closure, but mostly they clean, repaint, and fix anything broken. Water is unforgiving and the rockwork especially needs to be pressure washed and repainted often. They drain the ride during this time as well.
New lighting packages, for safety reasons as you said, could certainly be part of this winter's rehab, but the closure is not anything out of the ordinary.