hmm. I think this is too restrictive, its only the this new feature that requires 0.9.3. So instead should require 0.9.0 and raise and Import error as before. If its >= 0.9.0 but less than 0.9.3, just set a module level flag (e.g. something like ``_XLRD_093`` or something to False (and True otherwise); then raise if you are actually parsing an excel file and encounter a timedelta that needs this. Then we don't force users to upgrade unless they need the new capability.