According to prominent leaker Ice universe, the President of Samsung Greater China announced at an event that the company is planning to bring 25 W charging and a new low-light camera mode to the Galaxy S10. The device is supposedly already capable of charging at 25 W, but Samsung has limited it to 15 W in its firmware.
https://www.notebookcheck.net/Samsung-is-reportedly-already-planning-to-tweak-the-Galaxy-S10.415269.0.html