Sieve filter script regex

I have the following sieve script:

require ["enotify","body","regex","imap4flags","variables"];

if header :is "subject" "Sie haben eine Zahlung erhalten"
{
    if body :regex "Sie haben ([0-9,]+(\\.\\d{2})?) € EUR erhalten" {
        notify :importance "2" :message "Sie haben ${1} EUR erhalten" "mailto:xxxx@xxxx.com";
        setflag "\\Seen";
    }
}

But ${1} is not filled with my regex

Also tried to first set ${1} to a defined variable, also not working. What am I doing wrong?

The notifier itself is working, I get a mail but without a value.

I want to extract the amount from a body text: Sie haben 15,00 € EUR erhalten

So my regex should give me 15,00.

I'm not sure why, but body extension with :regex can not capture regex groups, but you still can use foreverypart and extracttext to assign body content into variable, so that string :regex can capture them.

Dovecot Pigeonhole Sieve's regex is quite limited, you can't use something like \d.

require ["enotify","regex","imap4flags","variables","foreverypart","extracttext"];

if header :is "subject" "Sie haben eine Zahlung erhalten"
{
    foreverypart {
        extracttext "body";
        if string :regex "${body}" "Sie haben ([0-9,]+(\\.[0-9]{2})?) € EUR erhalten" {
            notify :importance "2" :message "Sie haben ${1} EUR erhalten" "mailto:xxxx@xxxx.com";
            setflag "\\Seen";
            break;
        }
    }
}