In short
Sandstorm notifications and the activity log work again, and
Powerbox identity claims can be redeemed, without the Node 14 Cap'n Proto addon
that had switched them off: WeKan now speaks Cap'n Proto to the grain's bridge
in plain JavaScript, through a fork of capnp-es checked against the
reference C++ implementation. A booting grain also stops logging two false
warnings.
Thanks to above GitHub users for their contributions.