Version 0.56 is out, changes since v0.50:

• prevent running twice (if scheduled task hangs for some reason)
• send email notification if logfile is locked
• replace add-adgroupmember and remove-adgroupmember with set-adgroup because of a known bug in these commands
• multi-delete protection
• auto reconnect to Exchange Online when the connection times out + longer timeout
• additional filtering method for groups: extensionAttribute2
  • If you want to use this instead of the displayName prefix filter, read up on how to switch

Get it here