In reply to Giulio Daprela.

There is nothing in the GPL that says this isn't allowable.

Because of the freedoms provided by GPL license there is nothing stopping a user from editing the plugin files and bypassing the activation if they wish to do so.

So no, doing what you describe is not against the GPL.

The idea that the GPL requires you to make things easy for the user in this regard is a myth. It doesn't. The code can do whatever you want the code to do as long as the user still has the freedoms provided by the GPL.

Updates themselves are SaaS. They are also extremely important. I see nothing wrong, from a security and brand protection standpoint, with going this route to make sure the site the plugin is installed on has access to automatic updates.

If a user purchases the plugin for 1 site and installs it on a 100 sites that means 99 of his sites are not going to have automatic update. Do you think that user is going to keep those 99 sites updated manually? They are not. This means any security vulnerabilities that come up that you then patch via an automatic update are likely not going to be installed in a timely manner on those 99 other sites. Who do you think the user is going to blame in this situation? Himself? Unlikely. He's going to blame us. And he's going to do so publicly.

Having developed and supported one of the most popular commercial plugins in the WordPress ecosystem I can tell you I would prefer someone not use our product if they don't have automatic update access because of the negative impact it can have on our brand when they do so.

Deal with a security vulnerability in a popular commercial plugin and then let me know what you think of this scenario. You would have a massively different perspective.

We do not currently do this, but I see nothing wrong with it. It certainly isn't against the terms of the GPL.