I was trying to switch a [CultureSpecific(true)] [Required] propert to [CultureSpecific(false)]. And locally everything goes ok. But on the test server the change has not picked up. Maybe because there is some multicultural data already. I am not sure.
EPiServer verision is 10.3
The possible workaround I see here - simply to change this property via Admin->Content Types
Most probably data exist for those types in test environment, I doubt that via Admin also this will be possible without losing data.
So seems to be the only option is to Reset to default for the property...
In this case the master langage data will be still availible and all other languages data will be lost