If you are getting close to filling up your interface we strongly advice to start upgrading to the unlimited vcm licenses for those vehicles you have upgrade credits for.
Each single vcm license you license uses 1 slot on the interface
Each year/model license you license uses 1 slot on the interface
Each unlimited vcm license you license uses 1 slot on the interface
As you can imagine doing the unlimited vcm license for each vehicle group is going to be your best option whenever possible as having all of the unlimited vcm group licences would only use up a handful of licenses.
Our interfaces originally come with 400+ license slots on them which should be more than enough for most.
If you ever should run out of license slots on your interface you would need to purchase a new interface as if you were a new customer please contact sales at hptuners.com with your current serial number and we can link the tunerlock feature from the old interface to the new one so if you tunerlock your customers pcm's you will at least be able to read/write them with your new interface if the need arises.