MMR limit: Never exceeded 5400 since 1.6.2023 (that's June, dear Americans) and never exceeded 5700 since 1.1.2020
Prizepool: $300 (Top 8 payouts) + 580 OSC Points
Sponsor: MissCaVeiRa (<3) and OSC (http://sc2online.com)
Liquipedia:

We are partnered with and sponsored by the OSC for this event and players will be able to gain a total of 580 OSC Points from this event.
This event is also part of the Vulcan Circuit (for <5300 MMR players) and eligible players can gain Vulcan Circuit Points from this season. Liquipedia:

Schedule
SCHEDULING IS FLEXIBLE - This means that if the schedule does not work for you, you are allowed to play your games beforehand and hand in the replays. This is not possible for qualifiers and the final day (Ro8+) of course, because they are single-day events and not all matchups are known in advance.
Top 12 Qualify for each; 16 Invites for best-performing players from last season, 64 Total Players in Group Stage
Qualifier 1: Saturday, 14 October 2023 18:00 CEST
Qualifier 2: Saturday, 21 October 2023 18:00 CEST
Qualifier 3: Tuesday, 24 October 2023 18:00 CEST
Qualifier 4: Saturday, 28 October 2023 18:00 CEST
GroupStage Day 1: Saturday, 4 November 2023 18:00 - 22:00 CET (2 matches per player)
GroupStage Day 2: Saturday, 11 November 2023 18:00 - 22:00 CET (2 matches per player)
GroupStage Day 3: Saturday, 18 November 2023 17:00 - 23:00 CET (3 matches per player)
Ro32: Saturday, 25 November 2023 18:00 - 22:00 CET
< One week break for HomestoryCup. Players may optionally play their Ro32 or Ro16 match live at the public PCs at HSC if they want :D >
Ro16: Saturday, 9 December 2023 15:00 - 23:00 CET
Ro8+: Sunday, 10 December 2023 15:00 - 23:00 CET
The final two Days (Ro16 onwards) will be casted by

Region and Server
The event is open to all regions, but the server is always EU
You MUST join the Discord server to participate: https://discord.gg/5um65qS