[FactorAttractor]

You can permanently prolong the trial.
Not sure if anybody else knows about this, but just start the free premium trial and setup a network intercetpion proxy (fiddler is good).
Change the settings in malwarebytes to use fiddler as a network proxy.
In fiddler, use autoresponder to reset all requests to the malwarebytes activation server (I think it was keystone.malwarebytes.com or something similar).
There might have been another domain to block, not sure.

Updates will still work fine and after it exceeds the trial time, it will stay premium.

Just make sure that you never run malwarebytes without the proxy, otherwise it will connect to the activation server and deactivate the trial.