There are no mentions of new zpool features in the 11.2 release notes.
A zpool that reported no issues until 11.1p11, now reports:
$ zpool status
status: Some supported features are not enabled on the pool. The pool can
still be used, but some features are unavailable.
action: Enable all features using 'zpool upgrade'. Once this is done,
the pool may no longer be accessible by software that does not support
the features. See zpool-features(7) for details.
$ zpool upgrade
This system supports ZFS pool feature flags.
All pools are formatted using feature flags.
Some supported features are not enabled on the following pools. Once a
feature is enabled the pool may become incompatible with software
that does not support the feature. See zpool-features(7) for details.
Some mention of these new features should have been made in the release notes.
I suppose the correct course of action is to add them to the release errata.
I might be wrong, maybe only the following are new:
Also missing - the changes specifically relating to the "zpool remove" functionality.
There are significant differences in the 11.1-RELEASE zpool man page (zpool remove portion) vs. the 11.2-RELEASE man page.