EventKit watchOS 3.2 to 4.0 API Differences

EKCalendar.h
Declaration
From@property (nonatomic, strong, nonnull) EKSource *source
To@property (nonatomic, strong, null_unspecified) EKSource *source

Declaration
From@property (nonatomic, nonnull) CGColorRef CGColor
To@property (nonatomic, null_unspecified) CGColorRef CGColor

EKCalendarItem.h
Declaration
From@property (nonatomic, strong, nonnull) EKCalendar *calendar
To@property (nonatomic, strong, null_unspecified) EKCalendar *calendar

Declaration
From@property (nonatomic, readonly, nonnull) NSString *calendarItemExternalIdentifier
To@property (nonatomic, readonly, null_unspecified) NSString *calendarItemExternalIdentifier

Declaration
From@property (nonatomic, copy, nonnull) NSString *title
To@property (nonatomic, copy, null_unspecified) NSString *title

EKEvent.h
Declaration
From@property (nonatomic, readonly, nonnull) NSString *eventIdentifier
To@property (nonatomic, readonly, null_unspecified) NSString *eventIdentifier

Declaration
From@property (nonatomic, copy, nonnull) NSDate *startDate
To@property (nonatomic, copy, null_unspecified) NSDate *startDate

Declaration
From@property (nonatomic, copy, nonnull) NSDate *endDate
To@property (nonatomic, copy, null_unspecified) NSDate *endDate

Declaration
From@property (nonatomic, readonly, nonnull) NSDate *occurrenceDate
To@property (nonatomic, readonly, null_unspecified) NSDate *occurrenceDate

EKEventStore.h
Declaration
From- (nonnull EKSource *)sourceWithIdentifier:(nonnull NSString *)identifier
To- (nullable EKSource *)sourceWithIdentifier:(nonnull NSString *)identifier

Declaration
From@property (nonatomic, readonly, nonnull) EKCalendar *defaultCalendarForNewEvents
To@property (nonatomic, readonly, nullable) EKCalendar *defaultCalendarForNewEvents

Declaration
From- (nonnull EKCalendar *)defaultCalendarForNewReminders
To- (nullable EKCalendar *)defaultCalendarForNewReminders

Declaration
From- (nonnull EKCalendarItem *)calendarItemWithIdentifier:(nonnull NSString *)identifier
To- (nullable EKCalendarItem *)calendarItemWithIdentifier:(nonnull NSString *)identifier

EKStructuredLocation.h
Declaration
From@property (nonatomic, strong, nonnull) NSString *title
To@property (nonatomic, strong, nullable) NSString *title