silverpillActivityPub object identifiers are not IRIs. They are URIs:
https://www.w3.org/TR/activitypub/#obj-id
Unicode characters are not allowed there.
GNU social JP is a social network, courtesy of GNU social JP管理人. It runs on GNU social, version 2.0.2-dev, available under the GNU Affero General Public License.
All GNU social JP content and data are available under the Creative Commons Attribution 3.0 license.