Which specification (draft) of Sieve is used by Kolab?

[Fam. H. Bos]

Hello,

does anyone know where I can find the specification of the 
Sieve-command's currently used by Kolab.

When I issue the command sivtest I get the following info:

S: "IMPLEMENTATION" "Cyrus timsieved v2.3.16-kolab-nocaps"
S: "SASL" "PLAIN"
S: "SIEVE" "comparator-i;ascii-numeric fileinto reject vacation 
imapflags notify include envelope body relational regex subaddress copy"

But there is no way I can distinguish which "draft" of Sieve is actually 
used or what to select from the website: http://tools.ietf.org/wg/sieve/

So, Can anyone please give me some direction where I can find more about 
the Sieve command's?
B.t.w. I have the latest kolab version installed, i.e. kolab-2.3.2

Thx in advance,
Henk Bos.