IMHO, just keep to one "official" version, compatible with 1.5. User-made minimods to make the mod work with 1.6 should suffice; the RTRPE community is doing the same, with one of the team's unit balancing guys releasing an unofficial 1.6-compatible export_descr_unit.txt file every now and then for people who use the BI exe. 1.5 text files are compatible with 1.6, but the BI executable just adds a little bit more functionality.