Hm.. I see that there is a problem in Ubuntu but in Windows it seems to work. I tried the CSV translator with "minVersion": "4.0.27", but it works with "minVersion": "4.0.26", and every smaller number. The error message seems quite clear:

(2)(+0000001): Translate: Translation using CSV failed: 
string => TypeError: item.uniqueFields is undefined
stack => getValue@CSV:211:1
doExport@CSV:110:7

@dstillman Any ideas what is going on? Was there any change for uniqueFields in this version?

I don't really know anything about the uniqueFields stuff, sorry.

There are no uniqueFields in the API version of Zotero.Item JSON. https://github.com/zotero/zotero/blob/master/test/tests/data/translatorExport.js

Is uniqueFields old code and only supported for legacy translators (pre 4.0.27) via addCompatibilityMappings?

Please let me know whether it is true that: By increasing the minVersion to 4.0.27 the function addCompatibilityMappings will not be called. This could explain the problems with the translators commit...

Please let me know whether it is true that: By increasing the minVersion to 4.0.27 the function addCompatibilityMappings will not be called

That is correct.