Just wanted to add my interest in this feature being added too if possible.
I have my music stored on an SD Card in the tablet that I use Hi-Fi cast on, but my music is also stored on an external drive which is plugged into my router via USB. The router doesn't support DLNA, so SMB1 is the only way to go when trying to access it.
If Hi-Fi cast supported SMB1 access, I could use it from other tablets and phones aswell!
Would be great if SMB1 access was added. I wait with baited breath!
Many thanks in advance.