From personal experience on FreePBX I have found it is better just to not update anything and leave it alone. Most of the time updates will cause certain errors or Asterisk will just completely error out and cause the whole system to become nonfunctional. In this case I would recommend reverting to a backup or just completely reinstalling and starting over.
Andrew, when the user presses the restapps voicemail button in version 13.0.92, it shows these symbols i:0|0:0|u:0 on the display. I don’t understand what you mean when you say “its a mailbox”. Reverted back to 18.104.22.168 and it works fine.
The most recent version of Phone Apps included support for multiple voicemail boxes. The first press of the VM button lists all mailboxes the user has access to, and you then select from that list to view the mailbox contents
OK another note is Sangoma phones show the proper name for each box. Not sure why Aastra does not but we clearly state beyond Sangoma Phones that Phone Apps are best effort and we do no testing with other manufacture phones or have control so when we add things for our own phones it may break others. https://wiki.freepbx.org/display/FPG/Phone+Apps