Can we let our customers update the submitted data at some later date?

One thing I have been looking for (to steer away from MySQL type databases) is a way that people can update their responses on a form in real time (like dates that are available to work each month etc). Is there anything like that in JotForms?

Yes Martin, this is possible in several ways too.

You can update the submitted data at any time through the Submissions Panel, by clicking on Edit.

Now that would only allow you to edit it, but you can enable the people that submitted the forms to edit them as well and all it takes is to drag one option to your email body ;)

You can see here how to set it up like that: How to Let Users Update Their Form Submissions at a Later Date

Do let us know how it goes and we would be happy to assist :)