Upgrading Site Templates in the Solution Gallery

Question

How do I use the Upgrade button in the solutions gallery for a site template I've created? The word "upgrade" is forever associated with migration from 2010 to 2013, but unable to find prompt solution from google.

I've got a sort of nascent CRM built in SharePoint out of a bunch of forms and lists and such. A seriously contracted timeframe means that I'm having to roll the product out in pieces. This means I do development on a blank subsite, create a template from that site, and then... well, I'd like to be able to upgrade the activated template so users get that nice message that says "This site template has been updated, click here to update". But that doesn't work for me. And now that I'm up to about 18 subsites built on this template, trying to manage change on all of those subsites has gotten... stupid.

I've tried everything: recreating the template with the same name as the extant template, deactivating the in use template, deactivating both templates, activating both templates... nothing works.

Answer 1

In order to upgrade a solution, the new solution has to have the same solution ID as the currently active one, but a different file name.

This is usually fairly easy to achieve when creating sandbox solutions with VisualStudio - you just add your updates to the original VS project, and when you re-publish and get a .wsp file, it will have the same solution ID. Then you just have to rename the .wsp before you upload it to the solution gallery. SharePoint will recognize that it has the same solution ID as a currently active solution, and enable the Upgrade button.

Usually I end up post-fixing my solution name with the current version of the feature(s) it contains, like MySolutionName_v.1.0.0.0.wsp, that way it's easy to have a "different" file name without really having to change the name of the solution. (I.E. MySolutionName_v.1.0.1.0.wsp is technically a different file name.)

However, if you are creating site templates directly in SharePoint, I have no idea if this will work, or what mechanism is going on behind the scenes to assign a solution ID to your template. It's possible though that if you are always working on and adding to the same original site, if you save it as a template and download the .wsp file and rename it, then when you upload it to the solution gallery it might give you the upgrade option.