I do not know of anybody having performed successful hibernation with the pocket reform. Though I think @minute said in the past that suspend should work.
If you want to experiment with either, please overwrite the contents of /usr/lib/systemd/sleep.conf.d/reform-sleep.conf by copying that file as /etc/systemd/sleep.conf.d/reform-sleep.conf and change its content to at least say:
[Sleep]
AllowSuspend=yes
AllowHibernation=yes