Check for iOS 26 (can be modified for other versions too)

AppConfig.swift

struct AppConfig {
    static var isCompilerAtLeast62: Bool {
#if compiler(>=6.2)
        return true
#else
        return false
#endif
    }

    // This will only return true when built from Xcode 26 and for iOS 26 on other version it will return false.
    static var isOS26Available: Bool {
#if os(iOS)
        if #available(iOS 26.0, *) {
            return isCompilerAtLeast62
        } else {
            return false
        }
#elseif os(watchOS)
        if #available(watchOS 26.0, *) {
            return isCompilerAtLeast62
        } else {
            return false
        }
#endif
    }
}