We're aware of this issue, and it's not just with aussie.zone. It is related to the version disparity. The fastest way to fix it from our end would be to upgrade to the latest version in hopes that it would solve the federation issue, but that means breaking federation with instances that don't have the latest installed. It also means accepting whatever new bugs come with the new version, of which broken federation should be seen as a dead coal canary.
We plan to wait until the bugs in the new version are worked out. To restore interoperability with SLRPNK, aussie.zone will need to downgrade to the previous version. I apologize for the inconvenience. In the meantime, you can participate here with a SLRPNK account -- Welcome!