The Premier League transfer window has only just closed, but some teams immediately had another deadline to meet - registering their Champions League, Europa League or Conference League squads.
Clubs had to submit their senior team players to Uefa by 22:59 BST on Wednesday.
But squads are actually split into two separate lists - and there are a number of criteria that have to be met.
Here's how it all works.
Clubs must register a 'List A' and 'List B' squad.

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