The issue is with the output signature being declared in the last part
of the above line. It is trying to create a hierarchical block with a
variable number of output ports. This functionality is not yet
supported. In the past, we silently ignored this, and if the block
didn't actually try to use the feature, it would work okay. To be
more robust, we recently made this a hard error, which is why the
above error message started happening.
Looking at the code, it appears that all you need to do is change the
line to have an output signature of 1, 1 instead of 1, 2.
Johnathan