Comment 2 for bug 1620047

In accordance with this information https://wiki.php.net/rfc/switch.default.multiple on PHP.net in older php versions only the last "default:" statement would be used. It therefore should not break the code if the first "default:" clause is removed.

To "fix" the problem in avelsieve version 1.9.9 I manually did the following:

edit file /usr/share/squirrelmail/plugins/avelsieve/include/sieve_buildrule.inc.php
go to line 584 and comment out the "default:" line:

like this:
...
    switch ($rule['action']) {
    case '1': /* keep (default) */
/* default: commented out, only one default clause allowed */
        $out .= 'keep' . (!empty($flags_out) ? " $flags_out" : '' ) . ';';
        $text .= _("<em>keep</em> the message.");
        $terse .= _("Keep");
...