> ## Documentation Index
> Fetch the complete documentation index at: https://launchdarkly.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# iOS SDK 5.x to 6.0 migration guide for Objective-C
This topic explains how to adapt Objective-C code that currently uses a 5.x version of the [iOS client-side SDK](/docs/sdk/client-side/ios) to use version 6.0 or later. The sections in this topic address different changes and updates between versions 5.x and 6.0 of the SDK.
The Objective-C bridging types for the iOS SDK are implemented in Swift, where names are prefixed by `Objc`. This document refers to the types by the names exposed to Objective-C.
## Understanding the new LDValue type
The 6.0 release of the iOS client-side SDK introduces a new type that represents a value of any valid JSON type: `LDValue`. To learn more, read the [generated documentation](https://launchdarkly.github.io/ios-client-sdk/Classes/ObjcLDValue.html). You can initialize the `LDValue` type with different types of values to support arbitrary JSON data.
Here is an example:
```objectivec title="6.0 syntax" lines wrap theme={null}
LDValue *nullValue = [LDValue ofNull];
LDValue *boolValue = [LDValue ofBool:YES];
LDValue *numericValue = [LDValue ofNumber:@5.5];
LDValue *stringValue = [LDValue ofString:@"beta_testers"];
LDValue *complexValue = [LDValue ofDict:@{@"groups": [LDValue ofArray:@[[LDValue ofBool:YES]]]}];
```
## Understanding the changes to creating users
The `LDUser.custom` property has changed in type from `NSDictionary * _Nullable` to `NSDictionary * _Nonnull`.
Here is an example of the change:
```objectivec title="5.x syntax" lines wrap theme={null}
LDUser *user = [[LDUser alloc] initWithKey:@"example-user-key"];
user.custom = @{@"group": @"beta"};
```
```objectivec title="6.0 syntax" lines wrap theme={null}
LDUser *user = [[LDUser alloc] initWithKey:@"example-user-key"];
user.custom = @{@"group": [LDValue ofString:@"beta"]};
```
The `isEqual` function on `LDUser` has changed. It no longer only compares the `key` property, and now compares all properties of the instance.
```objectivec title="5.x syntax" lines wrap theme={null}
LDUser *user1 = [[LDUser alloc] initWithKey:@"example-user-key"];
user1.name = @"Jane Smith";
LDUser *user2 = [[LDUser alloc] initWithKey:@"example-user-key"];
user2.name = @"John Smith";
// Results in true
[user1 isEqual:user2]
```
```objectivec title="6.0 syntax" lines wrap theme={null}
LDUser *user1 = [[LDUser alloc] initWithKey:@"example-user-key"];
user1.name = @"Jane Smith";
LDUser *user2 = [[LDUser alloc] initWithKey:@"example-user-key"];
user2.name = @"John Smith";
// Results in false
[user1 isEqual:user2]
```
Setting `"custom"` as a private attribute no longer sets all custom attributes as private. The SDK considers only the custom attribute with the key `"custom"` as private.
## Changes to variation functions
The `LDClient` functions `arrayVariation` and `dictionaryVariation` have been removed. The new `jsonVariation` function lets you evaluate flags with any value type.
```objectivec title="5.x syntax" lines wrap theme={null}
NSArray *result = [[LDClient get] arrayVariationForKey:@"example-flag-key" defaultValue:@[]];
```
```objectivec title="6.0 syntax" lines wrap theme={null}
LDValue* result = [[LDClient get] jsonVariationForKey:@"example-flag-key" defaultValue:[LDValue ofArray:@[]]];
```
## Understanding changes to variationDetail functions
The `LDClient` functions `arrayVariationDetail` and `dictionaryVariationDetail` have been removed. The new `jsonVariationDetail` function allows evaluating flags with any resultant value type. The `LDJSONEvaluationDetail` type is used to store the resultant variation and detailed evaluation information.
The `reason` property of the detailed evaluation result types has also changed from `NSDictionary * _Nullable` to `NSDictionary * _Nullable`.
```objectivec title="5.x syntax" lines wrap theme={null}
LDArrayEvaluationDetail *result = [[LDClient get] arrayVariationDetailForKey:@"example-flag-key" defaultValue:@[]];
NSArray* resultValue = result.value;
NSDictionary *reason = result.reason;
```
```objectivec title="6.0 syntax" lines wrap theme={null}
LDJSONEvaluationDetail *result = [[LDClient get] jsonVariationDetailForKey:@"example-flag-key" defaultValue:[LDValue ofArray:@[]]];
LDValue* resultValue = result.value;
NSDictionary *reason = result.reason;
```
## Understanding the changes to flag value observers
The `LDClient` previously provided per-type functions for registering observers for flag values. These have been replaced with a single `observe` function you can use with flag variations of any JSON type.
```objectivec title="5.x syntax" lines wrap theme={null}
[[LDClient get] observeBool:@"example-flag-key" owner:self handler:^(LDBoolChangedFlag * _Nonnull changedFlag) {
Bool newValue = changedFlag.newValue;
}];
```
```objectivec title="6.0 syntax" lines wrap theme={null}
[[LDClient get] observe:@"example-flag-key" owner:self handler:^(LDChangedFlag * _Nonnull changedFlag) {
LDValue* newValue = changedFlag.newValue;
}];
```
## Recording custom events
If your application uses `track` to record `custom` events, you must remove the `error` parameter. The `track` functions no longer have the potential to error from invalid custom event data, because the `data` parameter is now restricted to the `LDValue` type. Change provided `data` types to `LDValue` instances.
Here is an example of the required changes:
```objectivec title="5.x syntax" lines wrap theme={null}
NSError* err = nil;
NSDictionary* data = @{@"abc": @123};
[[LDClient get] trackWithKey:@"key" data:data error:&err];
if (err != nil) {
// Do something with the error
}
```
```objectivec title="6.0 syntax" lines wrap theme={null}
LDValue* data = [LDValue ofDict:@{@"abc": [LDValue ofNumber:@123]}];
[[LDClient get] trackWithKey: @"key" data:data];
```