We have an app that receives, process and sends a string data in a particular format, I will explain better with a sample in that format. We have "AB-123456" where "AB" is always alphanumeric, "123456" is currently numeric, and "-" is the separator. We have a lenght and format restriction in place at our client side.

Now, we want to update the format to "AB-123456-1" to meet a new business requirement, but the client team doesn't agree with that since it will break their length restriction checks. But they are fine to use alphanumerals. One of the solution we proposed is to convert that number ("123456") to hex (we will get "1E240"), so the final representation of AB-123456-1 will become AB-1E2401. I would like to check whether there is an alternate solution available for this type of problem.