We have a number of agency clients who are using our CMS branded as their own. Lately we are getting a few emails about some problems that are being found, 6, 12 and even 24 month later.

We going to be pushing our product more this year and need to start thinking about how long we should be supporting each instance for, with the possibility for an adding support package to increase the support period.

In most instances I don't see clients paying extra for support. So on this basis does anyone know how long we should be supporting each instance of our CMS for? Support would include issues with the CMS, issues with any bespoke functionality, problems with the integration of the clients design, and problems caused by the client. I suppose we'd also need to support any new browsers and updates to any 3rd party scripts used.

Any ideas on what would be considered a reasonable timescale?