Troubleshooting - Connection Serial, Limitation, Queue, and upper limit

Problem Description:

How many concurrent connections does the Server edition support?

Is the product QB version specific, requiring additional purchases with each version? AKA. Upgrading from V15 to V16? 

Solution:

There is no limit on QODBC for the concurrent connection, but the more connections more QuickBooks has to work. QuickBooks SDK will process all the requests in a sequence, so if you have three connections and three queries going at the same time, SDK will execute it in sequence.

QODBC license is licensed for QuickBooks Version(Year). E.g., If you have QODBC Licensed for 2015, You can use QODBC with QuickBooks 2015,2014,2013, and so on, but not with QuickBooks 2016.

You can install QODBC v15 and v16 with no upgrade cost. Upgrade cost is only applicable when your license does not match the year.

For Example:

If you have QODBC licensed for 2015 & you are using QODBC v15 & QuickBooks 2015, you can install QODBC v16 and use it with QuickBooks 2015.