We build a system which works as software as a service. Now I am wondering if it is needed to give the version number to the clients. For example Facebook doesn't give a version number neither does Google. My question is basically would one include version numbers in an application where the client cannot change the version themselves?
Update 1
Just a quick update, yes we do offer an API and the API will be versioned in a similar way like Atlassian does api/ and then api/v2/ and so on.
The version number is just about the website the customer sees, not about developers.
Internally we use Jira for project management and there we also use the Jira releases feature. So internally we do have version numbers. Just not for the customers at the moment.
Best Answer
You might want to have internal version numbers of your application to better manage your internal development processes. However, these numbers are of little use for the user.
The usual purpose of version numbers is to tell the user if their application is up-to-date or not. When this is not within their control, it can at least be useful for support personnel to verify that they received the latest version. But when you have a software-as-a-service where all users share the same deployment, there is little reason to communicate the version number to them.
An exception could be when you aren't the only one who offers the service. When you only licensed the software or are licensing it yourself so others also offer the same software as a service, it could be useful to communicate the version number to the end-user so they can compare which provider offers which version and also be aware of the version used by their provider in case there are relevant differences in usage.