We were told last month that testing for an EOS-1D X Mark II replacement has begun.
We're now being told to expect an announcement for the camera between Q4 of 2019 and Q2 of 2020. As we've mentioned on a few occasions, the Summer Games are in Tokyo, Japan beginning in July of 2020.
While the source had no specific specifications, as it's far too early for that type of information to leak out, it was said to expect an evolutionary update and nothing revolutionary. The EOS-1D series simply has to work and be the workhorse professional photographers expect.
There was no word as to whether or not this would be the last of the EOS-1D X series DSLRs in favor of a mirrorless replacement in the future.
The source did suggest that we won't see the “pro” EOS R system camera until after the EOS-1D X Mark III hits the market.