diff --git a/chrome/content/zotero/xpcom/date.js b/chrome/content/zotero/xpcom/date.js
index c41b5eec50..d34c326a33 100644
--- a/chrome/content/zotero/xpcom/date.js
+++ b/chrome/content/zotero/xpcom/date.js
@@ -330,6 +330,8 @@ Zotero.Date = new function(){
 				}
 				
 				if(date.month) date.month--;		// subtract one for JS style
+				else delete date.month;
+				
 				Zotero.debug("DATE: retrieved with algorithms: "+JSON.stringify(date));
 				
 				parts.push(
@@ -369,7 +371,7 @@ Zotero.Date = new function(){
 		}
 		
 		// MONTH
-		if(!date.month) {
+		if(date.month === undefined) {
 			// compile month regular expression
 			var months = ['jan', 'feb', 'mar', 'apr', 'may', 'jun', 'jul',
 				'aug', 'sep', 'oct', 'nov', 'dec'];
diff --git a/chrome/content/zotero/xpcom/utilities.js b/chrome/content/zotero/xpcom/utilities.js
index 23ec452f1b..18fae8927b 100644
--- a/chrome/content/zotero/xpcom/utilities.js
+++ b/chrome/content/zotero/xpcom/utilities.js
@@ -99,6 +99,7 @@ const CSL_DATE_MAPPINGS = {
 
 /*
  * Mappings for types
+ * Also see itemFromCSLJSON
  */
 const CSL_TYPE_MAPPINGS = {
 	'book':"book",
@@ -1611,7 +1612,7 @@ Zotero.Utilities = {
 					cslItem[variable] = {"date-parts":[dateParts]};
 					
 					// if no month, use season as month
-					if(dateObj.part && !dateObj.month) {
+					if(dateObj.part && dateObj.month === undefined) {
 						cslItem[variable].season = dateObj.part;
 					}
 				} else {
@@ -1645,14 +1646,44 @@ Zotero.Utilities = {
 	 * @param {Object} cslItem
 	 */
 	"itemFromCSLJSON":function(item, cslItem) {
-		var isZoteroItem = item instanceof Zotero.Item, zoteroType;
+		var isZoteroItem = item instanceof Zotero.Item,
+			zoteroType;
 		
-		for(var type in CSL_TYPE_MAPPINGS) {
-			if(CSL_TYPE_MAPPINGS[type] == cslItem.type) {
-				zoteroType = type;
-				break;
+		// Some special cases to help us map item types correctly
+		// This ensures that we don't lose data on import. The fields
+		// we check are incompatible with the alternative item types
+		if (cslItem.type == 'book') {
+			zoteroType = 'book';
+			if (cslItem.version) {
+				zoteroType = 'computerProgram';
+			}
+		} else if (cslItem.type == 'bill') {
+			zoteroType = 'bill';
+			if (cslItem.publisher || cslItem['number-of-volumes']) {
+				zoteroType = 'hearing';
+			}
+		} else if (cslItem.type == 'song') {
+			zoteroType = 'audioRecording';
+			if (cslItem.number) {
+				zoteroType = 'podcast';
+			}
+		} else if (cslItem.type == 'motion_picture') {
+			zoteroType = 'film';
+			if (cslItem['collection-title'] || cslItem['publisher-place']
+				|| cslItem['event-place'] || cslItem.volume
+				|| cslItem['number-of-volumes'] || cslItem.ISBN
+			) {
+				zoteroType = 'videoRecording';
+			}
+		} else {
+			for(var type in CSL_TYPE_MAPPINGS) {
+				if(CSL_TYPE_MAPPINGS[type] == cslItem.type) {
+					zoteroType = type;
+					break;
+				}
 			}
 		}
+		
 		if(!zoteroType) zoteroType = "document";
 		
 		var itemTypeID = Zotero.ItemTypes.getID(zoteroType);
@@ -1667,9 +1698,14 @@ Zotero.Utilities = {
 		for(var variable in CSL_TEXT_MAPPINGS) {
 			if(variable in cslItem) {
 				var textMappings = CSL_TEXT_MAPPINGS[variable];
-				for(var i in textMappings) {
-					var field = textMappings[i],
-						fieldID = Zotero.ItemFields.getID(field);
+				for(var i=0; i<textMappings.length; i++) {
+					var field = textMappings[i];
+					
+					// Until 5.0, use version instead of versionNumber
+					if (field == 'versionNumber') field = 'version';
+					
+					var fieldID = Zotero.ItemFields.getID(field);
+
 					if(Zotero.ItemFields.isBaseField(fieldID)) {
 						var newFieldID = Zotero.ItemFields.getFieldIDFromTypeAndBase(itemTypeID, fieldID);
 						if(newFieldID) fieldID = newFieldID;
@@ -1677,10 +1713,12 @@ Zotero.Utilities = {
 					
 					if(Zotero.ItemFields.isValidForType(fieldID, itemTypeID)) {
 						if(isZoteroItem) {
-							item.setField(fieldID, cslItem[variable], true);
+							item.setField(fieldID, cslItem[variable]);
 						} else {
 							item[field] = cslItem[variable];
 						}
+						
+						break;
 					}
 				}
 			}
diff --git a/test/tests/data/citeProcJSExport.js b/test/tests/data/citeProcJSExport.js
index 3678e99098..67cb3f87ff 100644
--- a/test/tests/data/citeProcJSExport.js
+++ b/test/tests/data/citeProcJSExport.js
@@ -1347,8 +1347,7 @@
 					1,
 					2
 				]
-			],
-			"season": "2000-01-02"
+			]
 		},
 		"title": "Title",
 		"type": "patent"
diff --git a/test/tests/utilities.js b/test/tests/utilities.js
index 299a3fbb59..776b744a04 100644
--- a/test/tests/utilities.js
+++ b/test/tests/utilities.js
@@ -221,7 +221,7 @@ describe("Zotero.Utilities", function() {
 			
 			attachment.save();
 			
-			cslJSONAttachment = Zotero.Utilities.itemToCSLJSON(attachment);
+			let cslJSONAttachment = Zotero.Utilities.itemToCSLJSON(attachment);
 			assert.equal(cslJSONAttachment.type, 'article', 'attachment is exported as "article"');
 			assert.equal(cslJSONAttachment.title, 'Empty', 'attachment title is correct');
 			assert.deepEqual(cslJSONAttachment.accessed, {"date-parts":[["2001",2,3]]}, 'attachment access date is mapped correctly');
@@ -357,4 +357,62 @@ describe("Zotero.Utilities", function() {
 			assert.deepEqual(cslCreators[5], creators[5].expect, 'protected last name prevents parsing');
 		});
 	});
+	describe("itemFromCSLJSON", function() {
+		it("should stably perform itemToCSLJSON -> itemFromCSLJSON -> itemToCSLJSON", function() {
+			let data = loadSampleData('citeProcJSExport');
+			
+			Zotero.DB.beginTransaction();
+			
+			for (let i in data) {
+				let item = data[i];
+				
+				let zItem = new Zotero.Item();
+				Zotero.Utilities.itemFromCSLJSON(zItem, item);
+				zItem = Zotero.Items.get(zItem.save());
+				
+				let newItem = Zotero.Utilities.itemToCSLJSON(zItem);
+				
+				delete newItem.id;
+				delete item.id;
+				
+				assert.deepEqual(newItem, item, i + ' export -> import -> export is stable');
+			}
+			
+			Zotero.DB.commitTransaction();
+			
+		});
+		it("should import exported standalone note", function() {
+			let note = new Zotero.Item('note');
+			note.setNote('Some note longer than 50 characters, which will become the title.');
+			note = Zotero.Items.get(note.save());
+			
+			let jsonNote = Zotero.Utilities.itemToCSLJSON(note);
+			
+			let zItem = new Zotero.Item();
+			Zotero.Utilities.itemFromCSLJSON(zItem, jsonNote);
+			zItem = Zotero.Items.get(zItem.save());
+			
+			assert.equal(zItem.getField('title'), jsonNote.title, 'title imported correctly');
+		});
+		it("should import exported standalone attachment", function() {
+			let file = getTestDataDirectory();
+			file.append("empty.pdf");
+			
+			let attachment = Zotero.Items.get(Zotero.Attachments.importFromFile(file));
+			attachment.setField('title', 'Empty');
+			attachment.setField('accessDate', '2001-02-03 12:13:14');
+			attachment.setField('url', 'http://example.com');
+			attachment.setNote('Note');
+			
+			attachment.save();
+			
+			let jsonAttachment = Zotero.Utilities.itemToCSLJSON(attachment);
+			
+			let zItem = new Zotero.Item();
+			Zotero.Utilities.itemFromCSLJSON(zItem, jsonAttachment);
+			zItem = Zotero.Items.get(zItem.save());
+			
+			assert.equal(zItem.getField('title'), jsonAttachment.title, 'title imported correctly');
+		});
+	});
 });