In different scenario, this question can be different. In fact, this question can be seperated to several questions:
The most important thing is backup your previous configuration files.If there is any exception during the upgrade, we can roll-back to previous version.
Since all miniSIPServer configuraion files are stored in the application data directory, we just need to copy such directory to anywhere we want.
We can uninstall the previous version and install the new version in the same directory. The new version will detect, use and upgrade previous configuration files automatically.
Yes, you can. It is free to upgrade miniSIPServer from low version to higher version since they can share the same license. So just download the latest version and enjoy it.
First, you need download new 50 clients version from our website.
Since different licenses are used, you need pay the price differentials between these versions. Please visit our 'buy now' page to get details.
Once you get the new license, you can uninstall the previous 20 clients version and install the new 50 clients version, then input the new license to enable it. The upgrade process is almost same with above description.