Short Text Entry: Variable-length text entry with input mask

Users must input a string that is either 8 or 9 characters long. Most only have an 8 character code. Others have a 9 character code. I use the input mask @@*#####* but this will generate an error for users entering a string that is 8 characters long. Is there a way to make the 9th character optional? If not, is there a way to suppress the error?

Currently, it is not possible to have input masked while expecting variable-length. I am trying to come up with a workaround. I will be back as soon as possible.

The only workaround is to ask your users first the number of digits they have and then show/hide either the 8-digit or 9-digit masked input based on that. Please see my test form https://form.jotformpro.com/72004736147957.

I would escalate this to our developers to see if it is possible to have variable length text entry while applying an input mask.