Sometimes your customers think that time you’ve gave them for evaluation is not enough and you agree to give them more time. In this case you should provide them with extension license file. Let see how it can be done for the Unlock Key licensing schema. We suppose that you already have Product-Version-License Type tree created for your product. For this “How To” we suppose that it looks like the following:

The “LicenseByUnlockKey” license type implements “Unlock Key” licensing schema and is set up as following:

We suppose that most of the “Unlock Key” implementations have similar structure.

With “Unlock Key” licensing schema you have to distribute only one (master) license file with your product. Since your master license file already have been created and distributed to the clients with your product we can change existing license type to create extension license. First of all we should remove “Expiration Dates” format and add “Expiration Date” and “Is Extension” formats. New format list will looks like the following:

The “Is Extension” field indicates that new license file should override all licensing information stored in the license protected storage. It means that all expiration information have been stored with previous license file will be removed. The “Expiration Date” rule allows you set exact expiration date of the license file. It is necessary to not allow unlimited evaluation time. Pay attention that using of the other “Expiration” rules (“Expiration Dates” or “Expiration Runs”) in conjunction with “Is Extension” creates license file with potentially unlimited evaluation time. We strongly recommend using only “Expiration Date” rule when “Is Extension” format is included to the license type.

Now you should create extension license file. Create new sale under this license type and call it “Extension”, for example. Check “Write Key to File” checkbox, fill list of the NTP servers (if you are using it), and set new expiration date. Don’t create “Unlock Key”. The licensing information should looks like the following:

Save license file to the hard drive. Don’t rename it. Send license file to the customer who need extend evaluation time. Instruct customer to put license file to the “License” folder near you product. For example, is your product binary is installed as

C:\Program Files\Acme\My Product\ProductExecutable.exe

Then your customer should create “C:\Program Files\Acme\My Product\License” folder (if it is not there) and store license file you’ve sent to you in that place.