Some code for dealing with replacing pre-populated Core Data databases that are subject to change version by version. Place this in your `- (NSPersistentStoreCoordinator *)persistentStoreCoordinator` method.

CopyDatabase.m

// Main database location
NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"<#(DatabaseNameAndType)#>"];
 
NSFileManager *fileManager = [NSFileManager defaultManager];
NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// The Build/Bundle Version number of the application on launch
NSString *versionNumber = [[[NSBundle mainBundle] infoDictionary] objectForKey:(NSString*)kCFBundleVersionKey];

// Instead of using your app's bundle version create a custom key in your Info.plist for the database version. This is probably a better idea
// NSString *versionNumber = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"DatabaseVersion"];

// Get newest stored version from NSUserDefaults
NSString *newestNumber = [prefs stringForKey:NEWEST_RAN_VERSION];

// Check if either the database doesn't exist or if the application is a newer version than the previously stored version
if (![fileManager fileExistsAtPath:[storeURL path]] || ![newestNumber isEqualToString:versionNumber]) {
    // Get the database stored within your application's bundle
    NSString *bundledStorePath = [[NSBundle mainBundle] pathForResource:@"<#(BundledDatabaseName)#>" ofType:@"<#(BundledDatabaseType)#>"];
    
    if ([fileManager fileExistsAtPath:bundledStorePath]) { // If bundled database exists
        // Name of backup database and temporary backup database
        NSURL *backupStoreURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"<#(BackupDatabaseNameAndType)#>"];
        NSURL *secondBackupStoreURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"<#(TemporaryBackupDatabaseNameAndType)#>"];
 
        if ([fileManager fileExistsAtPath:[backupStoreURL path]]) {
            NSError *movedOldBackupError = nil;
            // Move database backup to temporary location. You may not want to do this depending on your database's size
            BOOL movedOldBackup = [fileManager moveItemAtURL:backupStoreURL toURL:secondBackupStoreURL error:&movedOldBackupError];
            if (!movedOldBackup) {
                NSLog(@"Failed to backup %@", [movedOldBackupError localizedDescription]);
            }
        }
        
        // Check if main database already exists
        if ([fileManager fileExistsAtPath:[storeURL path]]) {
            NSError *backupError = nil;
            // Backup main database to default backup location
            BOOL backedUp = [fileManager moveItemAtURL:storeURL toURL:backupStoreURL error:&backupError];
            if (backedUp) {
                if (![fileManager fileExistsAtPath:[storeURL path]]) {
                    NSLog(@"database moved successfully");
                    
                    // If the second backup exists, remove it
                    if ([fileManager fileExistsAtPath:[secondBackupStoreURL path]]) {
                        // If the database was backed up sucessfully remove the temporary backup
                        NSError *removedSecondBackupError = nil;
                        BOOL removedSecondBackup = [fileManager removeItemAtURL:secondBackupStoreURL error:&removedSecondBackupError];
                        if (!removedSecondBackup) {
                            NSLog(@"Failed to remove temporary backup %@", [removedSecondBackupError localizedDescription]);
                        }
                    }
                }
            } else {
                NSLog(@"Database backup failed %@", [backupError localizedDescription]);
            }
        }
        
        // Copy bundled database to the default location
        NSError *error = nil;
        BOOL copied = [fileManager copyItemAtPath:bundledStorePath toPath:[storeURL path] error:&error];
        if (copied) {
            // Set newest version number to NSUserDefaults
            NSLog(@"Copied new database");
            [prefs setValue:versionNumber forKey:NEWEST_RAN_VERSION];
            [prefs synchronize];
        } else {
            NSLog(@"Copy database error %@", [error localizedDescription]);
            
            // If database failed to copy attempt to copy the backup database to default location
            if ([fileManager fileExistsAtPath:[backupStoreURL path]]) {
                NSError *moveOldDatabaseError = nil;
                BOOL movedOldDatabase = [fileManager copyItemAtURL:backupStoreURL toURL:storeURL error:&moveOldDatabaseError];
                if (movedOldDatabase) {
                    NSLog(@"Copied old database to default location");
                } else {
                    // No database exists. Epic fail.
                    NSLog(@"Failed to copy old database %@", [moveOldDatabaseError localizedDescription]);
#warning Refrain from using `abort();` in production level code (says Apple)
                    abort();
                }
            }
        }
    }
}