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Even if this is way late, I’ll post an answer so anybody wondering can find the solution/reason:
In update 5.4, the way match lists are handled was changed. Whereas previously the lists were objects of the class you mentioned (ListMatchResponse), they are now just a generic list, List. These changes can be seen in this documentation: https://docs.unity3d.com/Manual/UpgradeGuide54Networking.html
As for how to fix this issue, you can go into the C# scripts specifically and change the various erroneous callbacks to reflect the current versions (again, seen in the docs above), but while that allows you to run the game, numerous other issues pop up. This is the bane of any networking in Unity, as it can get very hairy, very quickly. My suggestion would be to find a more recent/updated example project and try to work from that.
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