If you do concurrent, you will have to add a tracking mechanism to your app as well as an admin procedure where a user can bring up the list of connected users and clear them out in case a connection went dead before they could exit your app. You will have to be clever about this because this can lead to circumventing your concurrent use restriction. You will also need some reliable way of uniquely identifying the workstation running the app -- registry entry, MAC address of the ethernet card, etc.

You might use a timer that fires every 30 seconds of so to see if the connected user is still in the ConnectedUsers table. If their connection has been cleared, kick them out of the app and log this. If the problem persists [i.e., the log file grows consistently], have your app issue a nag warning everytime it launches saying that the concurrent connection license has being violated too many times and to contact you to clear the warning. Permit them to still run the app, but continue with the nag warning until you are contacted to turn it off. It goes away when you clear the log file, and comes back if they load it up again.

To clear the log file, have your app generate some random code based on the current date and time. Have them give you this code. On your end have a function that generates an unlocking code based on the value they give you. Have them enter the unlocking code. If the unlocking code they enter matching the unlocking code they would get based on the random code that your app generated, then open up the log file and zap it. I use this very method to activate workstations for one of my apps to prevent illegal copying of my software to other computer systems. I base this activation on the MAC address of the ethernet cards and store the activation info in the registry.

Who knows, maybe this type of licensing might actually increase your overall sales. I do not think doubling [or more] the per seat price will be effective in maintaining or increasing your sales because that would basically defeat the purpose of concurrent licensing. Your customer is looking to save money, while you are trying not to lose a sale. Unless you already have the capability to support concurrent licensing, the modifications you would have to make might not be worth the sale to just this 1 customer. You really need to determine how many licenses they are willing to pay for.

I also do not think I would look at this at how much I could lose. If you do not get the sale, you have lost 100% of whatever they were willing to pay for your product. Look at it from the point of how many more sales can you get if you pursue this method of licensing. You just have to weigh the benefits versus the cost of modifying your app to support this licensing type.

>We sell a VFP software (niche market) as a per seat license and one of our client has requested a concurrent licencing price to run our soft on a Citrix server.
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>I'm looking for a reference in regards with price because I don't know if I should multiply the price by 2, 5 or 10. I don't know how many seats per concurrent licence they will end up using really, so I don't know how much $ I could loose with this switch.
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>Any idea or existing pattern would be greatly appreciated.
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>TIA