Colons in notebook names cause zeppelin not to start

Using zeppelin 0.9 built 4/9/20, some users had created notebooks with colons in the name of the notebook. The build we had of 0.9 from about a week earlier happily created and used those notebooks. But when we tried to restart with this week's build it wouldn't start until we went in and manually renamed the notebooks from the command line to not have colons in the names.