A newer DAC, higher resolution USB DAC feature, USB-C interface, a metal case (some people here complaint about the current case), improved button layout (another complaint subject also).
Am I asking too much? I have just asked a simple question. If you don't know anything about possible updated version, just say you don't know. Is it really that hard?
There is no successor in the pipeline anytime soon.
The prolem with Tech is you can wait forever, because there is always something you could be waiting for with current development.
I would say, if you don't like the radsone es100 as is, maybe try searching for something that matches it with the upgrades you just mentioned.
I don't think you will be seeing a new version of the es100 anytime soon.
My 2 cents, if you can get it at a good price, jump straight on it, you won't be dissapointed.
If you get it at full price...you won't be dissapointed.,,,
In short....you won't be dissapointed.