is zpool upgrade safe in 15-stable

After updating my home server to 15-stable from 14-stable, I noticed there
are some extra new features available because of a newer import of ZFS. I
was wondering if the bootloader has been updated to allow booting from
these features?
Or is it OK to upgrade, but they can not be activated after?

Thanks
Dries


[/home/dries]$ 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.

Note that the pool 'compatibility' feature can be used to inhibit
feature upgrades.

Features marked with (*) are not applied automatically on upgrade, and
must be applied explicitly with zpool-set(7).

POOL  FEATURE
---------------
storage
      redaction_list_spill
      raidz_expansion
      fast_dedup
      longname
      large_microzap
      dynamic_gang_header(*)
      block_cloning_endian
      physical_rewrite
zroot
      redaction_list_spill
      raidz_expansion
      fast_dedup
      longname
      large_microzap
      dynamic_gang_header(*)
      block_cloning_endian
      physical_rewrite