Contacts watchOS 3.2 to 4.0 API Differences

CNContact.h
Modified CNContact
Protocols
FromNSCopying, NSMutableCopying, NSSecureCoding
ToNSCopying, NSItemProviderReading, NSItemProviderWriting, NSMutableCopying, NSSecureCoding

CNContactRelation.h
CNContactStore.h
Declaration
From- (nonnull NSString *)defaultContainerIdentifier
To- (nullable NSString *)defaultContainerIdentifier

CNError.h
CNPhoneNumber.h
Declaration
From+ (nonnull instancetype)phoneNumberWithStringValue:(nonnull NSString *)stringValue
To+ (nullable instancetype)phoneNumberWithStringValue:(nonnull NSString *)stringValue

Declaration
From- (nonnull instancetype)initWithStringValue:(nonnull NSString *)string
To- (nullable instancetype)initWithStringValue:(nonnull NSString *)string