From upgrading from 0.7.0 to 0.8.0 of python control library. I cannot find the sumblk function in matlab compatibility module in the version 0.8.0 Here is a link to documentation of previous release. https://python-control.readthedocs.io/en/0.7.0/matlab_strings.html#system-interconnections I cannot seem to find this in new release. I am also not able see the reason for this exclusion.