Push Notifications in Background, How to use URLSession?

From a strategy perspective I use BGAppRefreshTask and BGProcessingTasks, successfully implementing them for events triggered within the client application.

But there are certain events that are best triggered from the host, such as when we deploy a new set of vendor or price lists. We are trying to implement this background process using Push Notifications.

We have successfully implemented sending APNS notifications from the host and receive this .json message in.
application: didReceiveRemoteNotification: fetchCompletionHandler:

using this code:

-	(void)application:(UIApplication *)application didReceiveRemoteNotification:(nonnull NSDictionary *)userInfo fetchCompletionHandler:(nonnull void (^)(UIBackgroundFetchResult))completionHandler
{
	NSLog(@"userInfo - %@", userInfo);
	switch (application.applicationState)
	{
		case UIApplicationStateBackground:
		{
			//Check to see if this is a configs file update background notification
			NSArray *dictKeys	=	[userInfo allKeys];
			BOOL foundConfigs	=	NO;
			for (NSString *dk in dictKeys) if ([dk isEqualToString:kCONFIGSVERSION]) foundConfigs = YES;
			if (foundConfigs)
			{
				id configVersion		=	[userInfo objectForKey:kCONFIGSVERSION];
				NSLog(@"AAAppDelegate configVersion - %@", configVersion);
				if ([ServerUtilities deviceAssociatedWithAccount]) [self.bkSessionManager retrieveAndInstallUpdatedConfigFilesWithVersion:[configVersion integerValue]];
			}
			NSLog(@"AAAppDelegate remote notification handler");
			completionHandler(UIBackgroundFetchResultNewData);
		}
			break;
		case UIApplicationStateActive:
			NSLog(@"AAAppDelegate application is active");
			completionHandler(UIBackgroundFetchResultNoData);
			break;
		case UIApplicationStateInactive:
			NSLog(@"AAAppDelegate application is inactive");
			completionHandler(UIBackgroundFetchResultNoData);
			break;
		default:
			break;
	}

In the Xcode simulator running on an iPhone XS, we place the application in background and then send the APNS message from the host, receiving this .json message in the userInfo dictionary:

userInfo - {
    "app_version" = "0.1";
    aps =     {
        "content-available" = 1;
    };
    "configs_version" = 1;
    "dev_os" = 13;
    "os_type" = ios;
}

Receipt of this notification then triggers the client to initiate URLSession and retrieve the appropriate files from the host in order to update values on the client. As we are seeing inconsistent behavior we suspect that we are not implementing the URLSession properly.

When setting up the URLSession should it be configured using:

NSURLSessionConfiguration defaultSessionConfiguration

or

NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:

?

This is important to know since using backgroundSession requires us to set up the sessions as download tasks and the defaultSession as data tasks. I have tried various combinations so far without success.

Any leads here will help...