The Accelerator Neutrino Neutron Interaction Experiment (ANNIE) experiment is a 26-ton gadolinium-loaded water Cherenkov detector located on the Booster Neutrino Beam at Fermilab. The experiment has a two-fold motivation: to perform a physics measurement and to advance new detector technologies. The measurement of final state neutron multiplicity from neutrino interactions in water as a function of momentum transfer will lower systematic uncertainties for future long-baseline neutrino experiments. The experiment is currently commissioning large-area picosecond photodetectors (LAPPDs) that will improve time and spatial resolution. This marks the first usage of LAPPDs in a physics experiment. I will present some of the on-going work towards testing, characterization, and deployment of LAPPDs.