Zoho Sprints is a supposed to be a collaboration tool for project management but only supports 5 external users.  The profiles of those licenses cannot be modified and by default, the external users won't see any information about the project.  Every epic, sprint, user story and bug you would like your external client to see, you must specifically assign to them.  The solution is incredibly tedious and seems not to have gone through any serious degree of usability testing by Zoho.

Our company currently uses Zoho Projects but would prefer to move to Zoho Sprints which provides better support of agile processes.  In Zoho Projects, we have about 100 external users and there are no additional license costs. These client users look at the the project plan now and then, read task descriptions, and comment and reply to comments on various deliverables. The client collaboration in Zoho Projects works reasonably well and is affordable. 

In Zoho Sprints is the only option to get similar functionality to add another 100 staff licenses to our Zoho One subscription?