Save Game Variable Transfer

Development Programming & Scripting C++
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1

Say I have a USTRUCT, FCustomGameMode, that is UPROPERTY inside a USaveGame subclass, containing the following:

UENUM(BlueprintType)
enum class ESpawningPolicy : uint8
{
	None,
	OneAtATime,
	Multiple,
};

USTRUCT(BlueprintType)
struct FCustomGameMode
{
	GENERATED_BODY()

	UPROPERTY(EditDefaultsOnly)
	bool bUseBatchSpawning;

	UPROPERTY(EditDefaultsOnly)
	ESpawningPolicy SpawningPolicy;
};

Let’s say I decide I want to delete the boolean variable “Batch Spawning” and instead make an enum of it, shown below:

UENUM(BlueprintType)
enum class ESpawningPolicy : uint8
{
    None,
    OneAtATime,
    Multiple,
    Batch,
};

USTRUCT(BlueprintType)
struct FCustomGameMode
{
	GENERATED_BODY()

	UPROPERTY(EditDefaultsOnly)
	ESpawningPolicy SpawningPolicy;
};

How would I go about creating a function to update already existing SaveGames to this new design? More specifically, how would I access the old bUseBatchSpawning boolean variable and set the SpawningPolicy enum to “Batch”?

My main concern is how to reference a variable that is deleted. Could I somehow still access the property from older SaveGame where it still existed using its FName or something?

Thanks,
Mark