UP­ROP­ER­TY

• Ap­pend­ing _DEPRECATED to their name and re­mov­ing all meta­da­ta at­tributes.
• This will al­low blue­prints to still com­pile. I rec­om­mend re­mov­ing all us­es of the dep­re­cat­ed prop­er­ty dur­ing re­name in­stead of just refac­tor­ing the name of the sym­bol.
• Spec­i­fy DeprecatedProperty and DeprecationMessage in the UPROPERTY() macro for some ad­di­tion in­for­ma­tion to the us­er.

C++

UPROPERTY(EditAnywhere)
int32 Count;

UPROPERTY(meta=(DeprecatedProperty, DeprecationMessage="Use Size instead."))
int32 Count_DEPRECATED;

UFUNC­TION

• Adding the meta spec­i­fiers. You do not need to re­move the oth­er spec­i­fiers here nor re­name the func­tion.

C++

UPROPERTY(BlueprintPure)
int GetAnswerToEverything() const {…}

UPROPERTY(BlueprintPure, meta=(DeprecatedFunction,  DeprecationMessage="Use GetEarth() and GetAnswer() instead."))
int GetAnswerToEverything() const {…}

UCLASS

• These have a spe­cial Deprecated spec­i­fi­er that you should use to mark the class.
• You will need to re­name it:

C++

UCLASS()
class UMyObject : public UObject {
    GENERATED_BODY()
    /* ... */
};

UCLASS(Deprecated)
class UDEPRECATED_MyObject : public UObject {
    GENERATED_BODY()
    /* ... */
};

UENUM

• These don’t seem to have grace­ful means for be­ing dep­re­cat­ed.
• In the en­gine’s code you can find enum val­ues that are dep­re­cat­ed by suf­fix­ing them with _DEPRECATED.
• That is not nec­es­sar­i­ly “grace­ful” on its own, as in it isn’t picked up by the blue­print sys­tem and will cause com­pile er­rors there.

C++

UENUM()
enum class EMyEnum : uint32 {
    MyValue = 0,
    YourValue = 1,
    /* ... */
};

// After
/* @deprecated This was removed in version XY */
UENUM()
enum class EMyEnum_DEPRECATED : uint32 {
    /* @deprecated This was removed in version XY */
    MyValue_DEPRECATED = 0,
    /* @deprecated This was removed in version XY */
    YourValue_DEPRECATED = 1,
    /* ... */
};

• To en­sure blue­prints keep com­pil­ing, you can add redi­rects, e.g. in your DefaultEngine.ini:

INI

+EnumRedirects=(OldName="/Script/MyGame.EMyEnum",
    NewName="/Script/MyGame.EMyEnum_DEPRECATED",
    ValueChanges=(("MyValue","MyValue_DEPRECATED"), ("YourValue","YourValue_DEPRECATED")))

• Blue­prints will not is­sue a warn­ing, the us­er will at least see that _DEPRECATED suf­fix. hope­ful­ly hov­er over some­thing that shows the code com­ments in a tooltip and make nec­es­sary changes.
• Un­re­al En­gine Doc­u­men­ta­tion > Pro­gram­ming Guide > Core Re­di­rects for more in­for­ma­tion on redi­rects.

US­TRUCT

• Don’t seem to have grace­ful means of dep­re­ca­tion ei­ther. I sug­gest to ei­ther dep­re­cate the C++ side grace­ful­ly (see Non-Blue­print Types) and then dep­re­cate all the at­tributes:

C++

// Before
USTRUCT()
struct FMyStruct {
    GENERATED_BODY()
    /* ... */

    UPROPERTY()
    FString Name;
};

// After
USTRUCT()
struct DEPRECATED(4.20, "MyStruct is deprecated, use YourStruct instead.") FMyStruct {
    GENERATED_BODY()
    /* ... */

    UPROPERTY(meta=(Deprecated, DeprecationMessage="MyStruct is deprecated, use YourStruct instead."))
    FString Name_DEPRECATED;
};

Non-Blue­print Types

• DEPRECATED(version, message) macro:

C++

virtual void foo();

DEPRECATED(4.20, "Use bar() instead.")
virtual void foo();