So, 8MB and then doubling every 2 years.
I think block height rather than timestamp would be better for handling the doublings.
What is so special about the 11th January? Wouldn't 1st January make more sense?
This is the fork rule change.
The max message size is increased to the maximum block size for 2 hours into the future. This only applies to blocks though. All other messages are limited to 2MB.
The rule is 750 out of 1000 and then a 2 week delay until activation but not before Jan 11th.
The version is 0x20000004, so I guess that is to allow another soft fork to be run at the same time. It has some bitmask based stuff.
It seems complex to have to store the moment that the fork activates. Even if it activates late, using the default start time for the doublings shouldn't be that big a deal.