No, there will be no updates on the S50 other than paint color.
The carburated motor in the S50 makes a lot more power than the fuel injected motors in the C50 and M50. The three motors are actually very different, sharing only displacement for marketing reasons. The S50 is a legacy model, simply a renamed Intruder 800, which has been in production for over 15 years. The Intruder 800 was in turn based on the Intruder 750/ 700 series, which dates back over 20 years. So yes, the technology is not cutting edge, but it is a proven, reliable, bulletproof design that is the performance king of mid-sized cruisers.
As for its future, the S50 still sells pretty well, so replacing it with a new model is not a high priority for Suzuki. But because it is a legacy model that will eventually be replaced, there will be no major changes to it for the remainder of production.