Regardless of how long V10 has been baking - this is always a marketing thing.
I do not believe that PG would simply send a email to Steinberg Central saying “I’m done” and v10 starts rolling out the door.
As usual - Steinberg will take every opportunity to ensure this announcement comes to a wide audience via a major marketing event. I would be very surprised (Stunned actually) that a big “Version 10” of Wavelab would be release worldwide on some dead end Friday with no real marketing push.
If WL10 is a 2019 launch - my money is we hear about it here in Mid October 2019:
Does not get more “pro audio” than this.
Cheers,
VP