That could be the reason. In this case, you could try to update Shairport on your own (we do not currently offer this). You would have to follow these instructions: https://github.com/mikebrady/shairport-sync/blob/development/BUILDFORAP2.md
Unfortunately, we cannot give you any guarantee that the whole thing will work. It is also explicitly mentioned that this is a limited version of Airplay 2.