Index: src/helper.cpp
===================================================================
--- src/helper.cpp
+++ src/helper.cpp
@@ -37,13 +37,22 @@
     return (luminance > 128.0) ? QColor(0, 0, 0) : QColor(255, 255, 255);
 }
 
+static QString keyForCollectionColor(const Akonadi::Collection &coll)
+{
+    if (coll.remoteId().isEmpty()) {
+        qCDebug(CALENDARVIEW_LOG) << "Missing remoteId on collection" << coll.id() << coll.name() << "falling back to id";
+        return QString::number(coll.id());
+    }
+    return coll.remoteId();
+}
+
 void EventViews::setResourceColor(const Akonadi::Collection &coll, const QColor &color, const PrefsPtr &preferences)
 {
     if (!coll.isValid()) {
         return;
     }
 
-    const QString id = QString::number(coll.id());
+    const QString id = keyForCollectionColor(coll);
     if (coll.hasAttribute<Akonadi::CollectionColorAttribute>()) {
         Akonadi::CollectionColorAttribute *colorAttr
             = coll.attribute<Akonadi::CollectionColorAttribute>();
@@ -61,12 +70,17 @@
     if (!coll.isValid()) {
         return QColor();
     }
-    const QString id = QString::number(coll.id());
+    const QString id = keyForCollectionColor(coll);
     // Color stored in eventviewsrc (and in memory)
     QColor color = preferences->resourceColorKnown(id);
     if (color.isValid()) {
         return color;
     }
+    // Fallback for old config files which use ID instead of RemoteID
+    color = preferences->resourceColorKnown(QString::number(coll.id()));
+    if (color.isValid()) {
+        return color;
+    }
     // Color stored in akonadi
     if (coll.hasAttribute<Akonadi::CollectionColorAttribute>()) {
         Akonadi::CollectionColorAttribute *colorAttr