After updating to a recent mrtrix3 commit, I noticed that tck2connectome has different set of options. Notably, instead of -metric, there are options for weighting the edge in various ways. From the -help, I didn’t see an obvious choice for obtaining what the older versions would do for -metric meanlength.
Did I miss something?
In any case, I can still dump the assignments with tck2connectome and individual track lengths with tckstats and then construct the mean length connectome myself.