Id Fields now Strings?

[KatieK]

One of the big changes in Looker API Version 4.0 is that the majority of the id fields are now strings. 

Two questions:

1. Will these ids actually be non-numeric? Or can we safely cast them to numeric fields? (We store some of the ids in our database in fields with type bigint)
2. Is there a limit to the length of the string id field? (asking for the same reason- storage of the id fields in the database)

Thank you. 

[KatieK]

Got a response from Looker on this: 

[You] can't rely on any id field remaining numeric. That's why they were switched to string in API 4. They should be considered strings from this point forward.