If a player is replaced in an eSimulator/eSims match (eFootball, eBasketball…), is a new fixture created, or is the existing fixture updated?

Is the reason for the change (such as "player replacement") provided anywhere in the feed?

A replaced player in eSimulator product means a different team with different statistics/performance. Therefore, the fixture will be cancelled and a new one created. No specific reason is provided through the feed for the match itself, but it will be provided as a void_reason_id in the Bet Cancel messages when the markets get cancelled. Further info is provided via the client’s 24/7 Oddin.gg Trading chat.