The MAGIC telescopes, composed of two 17-meter diameter Imaging Air Cherenkov Telescopes (IACTs) situated 2200 meters above sea level on La Palma, detect very-high-energy gamma rays from the resulting Cherenkov air showers. They utilize a digital trigger system with an energy threshold of ~55 GeV. An alternative trigger, which sums analogue signals from adjacent regions of pixel groups, reduces the trigger threshold down to ~30 GeV. This Sum-Trigger-II recently allowed MAGIC to detect the Geminga Pulsar. We present detailed performance studies and operations of the Sum-Trigger-II system following a recent re-calibration period during Fall 2018 and Spring 2019. In addition, prospects and challenges for detecting GRB events with the Sum-Trigger-II, as well as potential future upgrades to the system, are discussed.