Various reliable sources have posted about the upcoming AKL-Jambo refurbishments and it appears people are starting to receive letters.

Pool & Pool Bar
Uzima Springs Pool and Uzima Springs Pool Bar are scheduled to be closed for refurbishment. During this time, Samawati Springs Pool and Maji Pool Bar at Disney's Animal Kingdom Villas - Kidani Village will be available. No set timeline on this other than closing September 3 through winter.

Rooms
Room refurbishments will be taking place. It is possible that guests may see or hear construction, but noise should not be heard from guest rooms between dusk and 9:00 a.m. Timeline is mid-August 2018 through Fall 2019.