Is this with a custom select field?

My guess is that the field is specified like this:

"example:versions": {
  "name": "Version",
  "type": "select",
  "options": ["A", "B", "C"]
}

If you use an object/map to specify the options instead of an array, you can choose the keys the options uses:

"example:versions": {
  "name": "Version",
  "type": "select",
  "options": {
    "A": "A",
    "B": "B",
    "C": "C"
  }
}

That should let you add, remove, and reorder values safely.

Assuming I'm right, you can swap by using numeric keys, e.g. change this:

["A", "B", "C"]

...to this:

{
  "0": "A",
  "1": "B",
  "2": "C"
}

That won't change any of the existing values (since we store 0/1/2 in the database), and you can then freely adjust the map from there.

yep you're right. Thanks! Is there a way to migrate to the new structure without losing all the data in existing fields?

The current structure has implicit keys "0", "1", "2", etc, so you can just make those implicit keys explicit. For example, change this:

["A", "B", "C"]

...to this:

{
  "0": "A",
  "1": "B",
  "2": "C"
}

If you browse around after making that change, all the data should still look the same.

Then you can add and rearrange keys freely. They don't need to go in a specific order or follow the same sequence. For example, if you add a new value with a more verbose key:

{
  "0": "A",
  "versionD": "versionD",
  "1": "B",
  "2": "C"
}

...that should not affect existing things with values "A", "B" or "C".

Cool, let us know if you run into anything else.