Kierre

### Description I've seen 2 Synapse homeservers spamming my server with queries for the same user. These are `cpluspatch.dev` (active) and `feline.support` (stopped a while ago, did it for several...

[Rendered](https://github.com/velikopter/matrix-spec-proposals/blob/edutypes/proposals/4373-edu-types.md)

Some room versions are incorrectly assumed to be v12

1

### Describe the bug Some rooms versions, like `org.matrix.msc3757.10`, make Cinny believe that we are creating a v12 room, when we are not: Rooms with these versions that already exist...