b. There is a confirmed incompatibility between OT 1.1.2 and PowerBook 3400s running Mac OS 7.6 (see Apple TIL file). The presumption was that this would be fixed with Mac OS 7.6.1. However, as reported by Eric (who is a 3400 owner) on the MRP, this appears not to be the case. The current recommendation is that 3400 owners should stay with OT 1.1.1.
c. In an issue that probably applies to all PowerBooks updated to 7.6.1 (which reduces the number of low battery warnings from three messages to two), Bryan Goldstein writes: "People are reporting that within just seconds of the first dialog box being dismissed, the second one comes up and the computer shuts off before the user has a chance to take any action (such as save the text or whatever). In addition, the computer often has to be restarted from a cold shut-down; there is not enough power left to keep the CPU in sleep mode."
Update: Several users report not having the low battery fast shut down problem.