Similar to Bug 27153, but for Zebra We understand we can add a transliterate rule in words-icu.xml, but would prefer to not maintain this on a server. It would be great if this could be toggled as a system preference, so that the rule is instance-specific.
I wonder how that could work with the Zebra configuration files as we cannot change them on the fly and manipulating the search query doesn't seem to be enough as I think you'd always have to change how things are indexed (ignoring apostrophes or not). I believe by default the normal apostrophes are ignored or could be added to the instance specific index configuration files (there is option option to have them instance specific IIRC, but we haven't used that feature)
From memory, Koha's Zebra config currently turns "David's" into "David s" using the ICU rules. I don't know allt he details of bug 27153, but we probably could use the XSLTs to add a z:index entry for title-no-punctuation that would be "Davids" and have title be "David's", and then the ICU rule will just affect "title" and not "title-no-punctuation". I haven't looked at bug 27153 in a while though, so I'd have to review it to know what we're doing there for sure. And actually... since the Zebra XSLTs are generated from the XML... it might be quite annoying to achieve this anyway...