manual page | zpool-features

Hello,

OpenBSD Packet Filter seems to have broken between 9.0 and 9.1, as it did 
from 8.2 to 9.0.  I built stable/9 and it was not fixed.  Since I like to 
run Packet Filter, I ran these commands:

# cd /usr
# svn co svn://svn.freebsd.org/base/head src

Then I checked /usr/src/UPDATING and found this:

20120828:
         A new ZFS feature flag "com.delphix:empty_bpobj" has been merged
         to -HEAD. Pools that have empty_bpobj in active state can not be
         imported read-write with ZFS implementations that do not support
         this feature. For more information read the zpool-features(5)
         manual page.

Unfortunately, I do not have a manual page for zpool-features.

Does this mean that I can not update from 9 to 10?  This amd64 has zfs 
root.

Darrel