I have a site template which I use to create sub-sites, hundreds of them. Creation of sub-sites is an ongoing process expected to continue on a regular basis.

The site template has a few lists and libraries, each of which is customised differently (different views, properties etc.). I keep on making changes to the site template, to the lists and libraries, as well as to the look and feel of the template. Though the new sub-sites incorporate the changes made till the point of creation, I am looking for some suggestion to push changes made to the site template to sites that have already been provisioned in the past. These include changes made to the lists/libraries, as well as the design elements.

Can anyone suggest what’s the best way to achieve this?

Many thanks!