diff -r eb56e743abe8 -r 0233da912ab6 mod_csi_muc_priorities/mod_csi_muc_priorities.lua
--- a/mod_csi_muc_priorities/mod_csi_muc_priorities.lua	Thu Apr 23 20:12:42 2020 +0200
+++ b/mod_csi_muc_priorities/mod_csi_muc_priorities.lua	Thu Apr 23 22:07:44 2020 +0200
@@ -105,11 +105,15 @@
 	end
 	local prioritized_jids = {};
 	if fields.unimportant then
-		for _, jid in ipairs(fields.unimportant) do
-			prioritized_jids[jid] = false;
+		if fields.unimportant then
+			for _, jid in ipairs(fields.unimportant) do
+				prioritized_jids[jid] = false;
+			end
 		end
-		for _, jid in ipairs(fields.important) do
-			prioritized_jids[jid] = true;
+		if fields.important then
+			for _, jid in ipairs(fields.important) do
+				prioritized_jids[jid] = true;
+			end
 		end
 	end