@kawia Sorry to hear you're having troubles. Unfortunately it's impossible to tell from just the information provided.
kawia ios17.5.1にアップデートした際に、skinの変更でアプリがクラッシュする現象が発生しております。
What exact error message do you receive? Could you perhaps share a log file or the message of the exception text?
Does the issue happen with all your skeleton assets, or just a single one?
Could you share a minimal Unity project which still shows this issue? You can send it as a zip file to contact@esotericsoftware.com, briefly mentioning this forum thread URL so that we know the context. Then we can have a look at what's going wrong.