Can a JS client (Angular JS 1.X) connect to, two different servers. First one is: Signalr.Net (old version) and second is: Signalr Core (.Net core version) simultaneously.
In other words, can both SignalR Js client libraries co-exist, in same JS application.
On server side we have two different servers hosting both versions separately.
Are there any performance disadvantages?
No you cannot use those together. Check my answer here for why and links to the documentation that state the same.
SignalR version compatability (StatusCode: 405 'Method Not Allowed')
You can't mix the .NET Core 1.x with the older client (1.x or 2.x). You will need to decide which is the best option for you but you need to implement the same compatible version across CLIENT and SERVER.
Check the link for more details but essentially:
What’s Changed?
We added a number of new features to SignalR for ASP.NET Core but we also decided to remove support for some of the existing features or change how they work. One of the consequences of this is that SignalR for ASP.NET Core is not compatible with previous versions of SignalR. This means that you cannot use the old server with the new clients or the old clients with the new server.
