iOS 9.3 is coming in the Spring and will introduce Night Shift as well as a number of other new features.
Powerbook/iBook Battery Recall
12-inch iBook G4 A1061 HQ441 - HQ507
12-inch PowerBook G4 A1079 3X446 - 3X510
15-inch PowerBook G4 A1078 3X446 - 3X509
Powerbook batteries have previously been subject to recall in August of 2004.