Recommendations

We recommend manually converting the update sections to the new method. The biggest change that confuses people is the old += operator does not work the same way as before.

Instead of doing:

Reply-Message += "foo"

you should edit the reply list, using the += operator:

reply += {
    Reply-Message = "foo"
}

We also recommend removing double-quotes from xlat expansions where possible. The temptation in v3 is to just add double quotes to everything, and hope it all works out. This is no longer necessary in v4.

For example, in v3 you would do:

update reply {
	Framed-IP-Address := "%{sql:SELECT ...}"
}

In v4, you can remove the update, and rewrite the SQL call to:

reply.Framed-IP-Address := %sql("SELECT ...")

Using double quotes everywhere means that every bit of data gets converted to printable strings, and then back to it’s real data type (ipaddr in the above example). Removing the double quotes means that there is less work going on, which means higher performance.

Best Practise

In v3, many people had a habit of just adding "…" around everything. For example:

Bad practice - using "" everywhere

update reply {
	Reply-Message := "%{User-Name}"
}

...

if ("%{User-Name}" == "bob") {
   ...
}

This practice is not recommended. It was never necessary, and it’s not clear why it became a (bad) habit.

In v4, it is clearer, simpler, and faster to just use unlang syntax correctly.

Good practice - just rely on the server to do the right thing

reply.Reply-Message := User-Name

...

if (User-Name == "bob") {
   ...
}