     required: [ 'itemID', 'legacy', 'skipChildItems' ]
   }
 })
+if (coll.getTransform(METADATA)?[0].value || {}).Zotero != zotero_config.Zotero.version
+  debug('CACHE: dropping cache', coll.name, 'because Zotero is now', zotero_config.Zotero.version)
+  coll.removeDataOnly()
+coll.setTransform(METADATA, [{
+  type: METADATA,
+  value : { Zotero: zotero_config.Zotero.version }
+}])
 
 ###
   TODO: for this to work, an object must be updated when it is fetched

    coll.findAndRemove(query)
  return

DB.schemaCollection('itemToExportFormat', {
  indices: [ 'itemID', 'legacy', 'skipChildItems' ],
  schema: {
    type: 'object'

ttl =         1000  * 60  * 60  * 24 * 30
ttlInterval = 1000  * 60  * 60  * 4
for translator of Translators.byName
  coll = DB.schemaCollection(translator, {
    indices: [ 'itemID', 'exportNotes', 'useJournalAbbreviation' ],
    schema: {
      type: 'object'
