Bug fixes http://www.examiner.com/article/minecraft-for-pc-to-get-1-3-2-update-this-week I would wait on EMC to say its ok before you update though just incase
Yes because *Turns on Smart Mode* 1.3.2 only contains bug fixes and no new entities or blocks which means 1.3.2 and 1.3.1 are compatible. Take 1.2.3 and 1.2.4 as an example.