Precisely one more episode is added to the schedule that wasn’t already there.
We now know the Detective Conan anime’s broadcast schedule for one more week in December. That leaves just three more, one of which is likely to be a break, and two of which are almost certainly going to be the “Haibara’s Lost Phone Strap” case.
December 1st was already included in the reveal for November. To recap, episode 923, an anime original titled “A Day Without Conan,” will air on that date.
Episode 924 is now slated to broadcast on December 8th. It will be an anime original titled “An Orange Grove in Sunset.”
The anime typically takes a break the last weekend of the year, which this year will be December 29th. So, that leaves December 15th and 22nd to air the “Haibara’s Lost phone Strap” from the manga as a two-parter. That case directly leads into the events of the “Crimson School Trip” case, slated for January 5th and 12th, so there should be no chance it gets pushed back to later on the schedule, as the anime sometimes does.
Still, as likely as that may be, nothing is official until they’ve announced it.