Well, the administrator's guide, chapter 14, in the file replication.html distributed with the package openldap2 does not mention deprecation.
Always read up to date docs when you can or search our archives.
ITS #5196 ?
This is why I filed that ITS, as it is quite obvious that it would have been useful if the last 2.3 release indicated the obsolescence of slurpd ...
Regards, Buchan