treecorr > 4 has some small changes which break validate_drp.
Specifically, varxi in ggcorrelation has been removed.
There is varxim and varxip, described here:
The use is in line 187 python/lsst/validate/drp/calcsrd/tex.py.
Treecorr <4 also does not have varxim or varxip, so this ticket will likely require a merge of a new environment with treecorr > 4 as well.
It appears this is possibly a blocker for moving to python 3.8, due to conda-forge wanting treecorr > 4 for python 3.8 (I am not sure why - I have not checked the recipes at this point).