Additional Information
The SystemLink Base and SystemLink Server installers are almost identical. Assuming you've installed all the SystemLink Base modules you want to use in SystemLink Server, the only change needed is a licensing change. The SystemLink Base "Small" and "Medium" licenses are unchanging local licenses. All you need to do to expand beyond the 10 users and 25 connected systems allowed by the SystemLink Base "Medium" license is to disable the "Medium" local license and configure your SystemLink Base computer to use SystemLink Server licenses hosted by the NI Volume License Manager (NI VLM).
The only computer that ever checks out any SystemLink Server licenses from NI VLM is the computer where SystemLink Base or SystemLink Server are installed. That means any explicit license assignments should ALWAYS be configured for the SystemLink Server computer, not for any client system computers or connecting users. If you see any SystemLink Server User-Based licenses in NI VLM, then that was a mistake in the *.lic file, and you should ask for a new one.