We should offer an easy way to upgrade from GRS1 to DOM indexing. People could use it manually now and it should be part of the upgrade process to 3.20 or legacy (-ish package) installations will break. zebra-biblios-dom.cfg creation could be done with something like sed -e "s/__KOHASITE__/instancename/g" \ -e "s/__ZEBRA_MARC_FORMAT__/marcflavour/g" \ -e "s/__ZEBRA_LANGUAGE__/en/g" \ "/etc/koha/zebra-biblios-dom-site.cfg.in" > "/etc/koha/sites/instancename/zebra-biblios-dom.cfg" maybe for all instances found by koha-list. koha-conf.xml has to be checked for zebra_*_index_mode and use_zebra_facets and they need to be changed or added, the xi: stuff has to be added to the biblioserver section. Zebra restarted and rebuilt afterwards.
zebra-biblios-dom.cfg gets added by the packages anyway, so it's just the koha-conf.xml changes.
Time for this has passed I guess.