❔ StringSyntax attribute not available

Yesterday I updated VS to the latest version and installed .NET SDK 7 but whenever I try to use

[StringSyntax(StringSyntaxAttribute.Regex)]

[StringSyntax(StringSyntaxAttribute.Regex)]

on a parameter, VS doesn't seem to be able to find it for importing. My project uses .net v4.8.1 framework.

❔ StringSyntax attribute not available - C#