Historically, these keyboards have been released every two years. As the PSR-E373 and EW310 were released last year, then that would point to their replacements being introduced sometime next year. In reality, as it has taken so long for the E473 and EW425 to be released, I would not be surprised to see a release date in the 2023 range, or even later, for the E383 and EW325... if that's what they'll even be called. As always, this is pure speculation on my part.