The T-15 saw service with the Galactic Empire until its eventual replacement with newer models.
During the conflict on Mimban, a swamp trooper communicated to a fellow soldier that the T-15 transports were inoperable, forcing them to proceed on foot.
Speculation arose that the T-15s would soon be deemed obsolete around the time of the Battle of Scarif. This was overheard in a conversation between two stormtroopers, just prior to their incapacitation by Chirrut Îmwe, who expressed anticipation for this obsolescence.
The T-15 references present in Rogue One: A Star Wars Story and Solo: A Star Wars Story originated from voice actor Sam Witwer. They were included as a nod to a dialogue exchange in Star Wars: Episode IV A New Hope, where two stormtroopers discuss the BT-16 while Obi-Wan Kenobi deactivates the tractor beam. Witwer also incorporated comparable lines into the sequel trilogy, referencing the T-17 and T-18. A parallel reference to the T-16 was inserted into "Part III" of the Obi-Wan Kenobi series. The specific model mentioned was determined by the time period.