The version of xcode is 10, but the project does not appear in the migration option. I want to know why.

I installed the latest version of xcode and tried to open the project's work area and an alert appeared saying that I would need to migrate to version 4.x, because the current one is in 3.x and for that I would need to download version 10 of xcode for migrate. That was done. But, in the errors / alerts panel, there is no such quick migration notification either (Edit menu - Convert - For the current Swift syntax)