--- a/util/prosodyctl/shell.lua	Sun Apr 25 17:20:58 2021 +0200
+++ b/util/prosodyctl/shell.lua	Sun Apr 25 17:27:02 2021 +0200
@@ -74,7 +74,8 @@
 	if arg[1] then
 		if arg[2] then
 			-- prosodyctl shell module reload foo bar.com --> module:reload("foo", "bar.com")
-			arg[1] = string.format("%s:%s("..string.rep("%q", #arg-2, ", ")..")", table.unpack(arg));
+			-- COMPAT Lua 5.1 doesn't have the separator argument to string.rep
+			arg[1] = string.format("%s:%s("..string.rep("%q, ", #arg-2):sub(1, -3)..")", table.unpack(arg));
 		end
 
 		client.events.add_handler("connected", function()