diff --git a/chrome/content/zotero/xpcom/citeproc.js b/chrome/content/zotero/xpcom/citeproc.js
index 4753b99d6..4246773a5 100644
--- a/chrome/content/zotero/xpcom/citeproc.js
+++ b/chrome/content/zotero/xpcom/citeproc.js
@@ -1732,7 +1732,7 @@ CSL.DateParser = function (txt) {
 };
 CSL.Engine = function (sys, style, lang, forceLang) {
 	var attrs, langspec, localexml, locale;
-	this.processor_version = "1.0.110";
+	this.processor_version = "1.0.111";
 	this.csl_version = "1.0";
 	this.sys = sys;
 	this.sys.xml = new CSL.System.Xml.Parsing();
@@ -3975,7 +3975,7 @@ CSL.Node.key = {
 								state.output.append(CSL.Util.Dates[e]["numeric-leading-zeros"](state, value));
 							}
 						}
-						if (state.registry.registry[Item.id].disambig.year_suffix) {
+						if (state.registry.registry[Item.id] && state.registry.registry[Item.id].disambig.year_suffix) {
 							num = state.registry.registry[Item.id].disambig.year_suffix.toString();
 							num = CSL.Util.padding(num);
 						} else {