Dropbox Error Opens Another App on device, not on simulator - ios

Question

I have three apps that upload files to Dropbox. Same code for all three. They all share the same folder so I've used same secret key etc
Heres where it gets weird
1. All was fine for few months
2. Now on apps 2 and 3 when the user tries to log in it opens the first app?
3. Logging out and in, no help, just says Theres a an error connecting to Dropbox and to try later
What ive tried
Creating seprate secret keys etc for all three apps rathe rthan sharing the same, still get the same behaviour?
Some research on this suggested that Dropbox has changed the way it links to users accounts through applications and remins linked even if you delete the app? Has anyone else got any experience with this?
Appdelegate
NSString* appKey = #"00000000000";
NSString* appSecret = #"0000000000";
NSString *root = kDBRootAppFolder;
DBSession* session =
[[DBSession alloc] initWithAppKey:appKey appSecret:appSecret root:root];
session.delegate = self; // DBSessionDelegate methods allow you to handle re-authenticating
[DBSession setSharedSession:session];
[DBRequest setNetworkRequestDelegate:self];
Button Handler in viewController
LogCmd();
self.publishButtonPressed = YES;
if (![[DBSession sharedSession] isLinked]) {
[self loginLogoutButtonPressed:nil];
} else {
DBRestClient *restClient = [[DBRestClient alloc] initWithSession:[DBSession sharedSession]];
restClient.delegate = self;
NSError *error = nil;
NSString *filePath = [ICUtils pathForDocument:self.fileName];
[self.pdfData writeToFile:filePath options:0 error:&error];
if (nil == error) {
[restClient uploadFile:self.fileName
toPath:#"/"
withParentRev:nil
fromPath:filePath];
} else {
[ICUtils raiseAlertWithTitle:#"An error occurred" message:[error localizedDescription]];
}
}
}
Note works ok on the simulator, problem is only present on device

Answer 1

That is because you are using the same key for multiple applications. The Dropbox app is communicating with your app through a custom URL scheme - to launch your app (because there is no other way to launch apps programmatically on iOS).
In other words, the Dropbox app tells the system to open "db-yoursecretkey://somemessage" which opens the registered app for that custom URL scheme. Unfortunately, all of your apps use the same custom scheme as they are all using the same key, so the system just picks one: most likely the first one.
However, you can grant your apps access to all folders in dropbox, thus effectively sharing folders. So it's not really necessary to have all three apps using the same key.