diff --git a/HISTORY.md b/HISTORY.md
index d76c5aaf..d47b5ae0 100755
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -8,9 +8,13 @@
* **Notable Changes:**
* when creating a costume from pen trails (raster or vector) make its rotation center the position of the sprite
* **Notable Fixes:**
+ * support null-serialization in list-csv conversions
* **Translation Updates:**
* German
+### 2019-12-08
+* lists: support null-serialization in list-csv conversions
+
### 2019-12-07
* threads: turn "log pen trails" off when loading or creating a new project
diff --git a/snap.html b/snap.html
index 4c9a7322..53da4fd9 100755
--- a/snap.html
+++ b/snap.html
@@ -11,7 +11,7 @@
-
+
diff --git a/src/lists.js b/src/lists.js
index 9d78c650..119875ea 100644
--- a/src/lists.js
+++ b/src/lists.js
@@ -62,7 +62,7 @@ CellMorph, ArrowMorph, MenuMorph, snapEquals, Morph, isNil, localize, isString,
MorphicPreferences, TableDialogMorph, SpriteBubbleMorph, SpeechBubbleMorph,
TableFrameMorph, TableMorph, Variable, isSnapObject, Costume, contains*/
-modules.lists = '2019-November-15';
+modules.lists = '2019-December-08';
var List;
var ListWatcherMorph;
@@ -425,7 +425,7 @@ List.prototype.asCSV = function () {
rows = [];
function encodeCell(atomicValue) {
- var string = atomicValue.toString(),
+ var string = isNil(atomicValue) ? '' : atomicValue.toString(),
cell;
if (string.indexOf('\"') === -1 &&
(string.indexOf('\n') === -1) &&